U.S. patent application number 11/030362 was filed with the patent office on 2005-09-22 for advanced multi-pressure workpiece processing.
Invention is credited to Barker, David Alan, Devine, Daniel J., George, Rene, Pakulski, Ryan Michael.
Application Number | 20050205210 11/030362 |
Document ID | / |
Family ID | 34794284 |
Filed Date | 2005-09-22 |
United States Patent
Application |
20050205210 |
Kind Code |
A1 |
Devine, Daniel J. ; et
al. |
September 22, 2005 |
Advanced multi-pressure workpiece processing
Abstract
Workpiece processing uses a transfer chamber in cooperation with
a process chamber. The workpiece is to be heated to a treatment
temperature, at a preheating pressure, and subsequently exposed to
a plasma at a treatment pressure, which is less than the preheating
pressure. The process chamber pressure does not exceed the
preheating pressure, yet very rapid pressure increases can be
induced in the process chamber in transitioning from the treatment
pressure to the preheating pressure. The transfer chamber pressure
can be maintained at the treatment pressure, the preheating
pressure or raised to a selected pressure to backfill the process
chamber to the preheating pressure. A backfill arrangement can
selectively induce rapid pressure increases in the process chamber.
A bypass arrangement provides selective pressure communication
between the transfer and process chambers and can be used for
backfilling the process chamber from the transfer chamber.
Inventors: |
Devine, Daniel J.; (Los
Gatos, CA) ; George, Rene; (San Jose, CA) ;
Pakulski, Ryan Michael; (Discovery Bay, CA) ; Barker,
David Alan; (Walnut Creek, CA) |
Correspondence
Address: |
PRITZKAU PATENT GROUP, LLC
993 GAPTER ROAD
BOULDER
CO
80303
US
|
Family ID: |
34794284 |
Appl. No.: |
11/030362 |
Filed: |
January 5, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60534495 |
Jan 6, 2004 |
|
|
|
Current U.S.
Class: |
156/345.32 ;
118/719; 216/67 |
Current CPC
Class: |
H01L 21/67748 20130101;
C23C 16/45557 20130101; H01J 37/32743 20130101; H01J 37/32935
20130101; H01L 21/67017 20130101; G03F 7/427 20130101; H01L
21/67196 20130101; C23C 16/54 20130101 |
Class at
Publication: |
156/345.32 ;
118/719; 216/067 |
International
Class: |
C23F 001/00 |
Claims
What is claimed is:
1. In a system for treating at least one workpiece using a
treatment process, said system having at least a transfer chamber
and a processing chamber such that a transfer chamber pressure, in
the transfer chamber, and a processing chamber pressure, in the
processing chamber, can each vary and the workpiece can be moved
between the transfer chamber and the processing chamber, said
system further including a process gas regulation arrangement for
providing process gas to said processing chamber at least during a
plasma treatment process at a given flow rate and which is capable
of providing said process gas at a maximum flow rate, a method
comprising: a) equalizing the transfer chamber pressure and the
processing chamber pressure to a treatment pressure at which the
workpiece is to be subjected to a plasma treatment process; b)
transferring the workpiece from the transfer chamber to the
processing chamber at the treatment pressure; c) preheating the
workpiece to a treatment temperature, in cooperation with raising
the processing chamber pressure to a preheating pressure at a
pressure rise rate resulting at least in part from using an
additional process chamber gas input flow at an input flow rate
which causes an overall input rate to the processing chamber to be
greater than said maximum flow rate, without raising the transfer
chamber pressure; d) reducing the processing chamber pressure to
the treatment pressure; and e) exposing the workpiece to said
plasma treatment process at least approximately at said treatment
pressure and at said treatment temperature.
2. The method of claim 1 wherein said pressure rise rate is at
least 15 Torr per second.
3. The method of claim 1 wherein said workpiece supports a
photoresist layer and wherein said preheating and exposing
cooperate in removing the photoresist layer using said plasma
treatment process.
4. The method of claim 3 wherein said plasma treatment process
produces a plasma which is customized for removing said photoresist
layer from the substrate at said treatment temperature.
5. The method of claim 1 wherein said workpiece is supported by a
susceptor and including heating the susceptor for use in preheating
the workpiece.
6. The method of claim 5 wherein heating includes heating the
susceptor to an at least approximately fixed temperature.
7. The method of claim 1 wherein said treatment pressure is in a
range from approximately 0.01 to 10 Torr.
8. The method of claim 1 wherein said treatment pressure is
approximately 1 Torr.
9. The method of claim 1 wherein said preheating pressure is in a
range from approximately 25 to 250 Torr.
10. The method of claim 1 wherein said preheating pressure is at
least approximately 60 Torr.
11. The method of claim 1 wherein preheating includes introducing a
preheating gas mixture into the processing chamber for enhancing a
rate of temperature increase of the workpiece.
12. The method of claim 11 including using helium gas as at least a
portion of the preheating gas mixture.
13. The method of claim 1 including configuring a backfill
reservoir arrangement for selective pressure communication with
said processing chamber for use in selectively producing a pressure
increase in said processing chamber by causing said additional
process chamber input flow, and preheating the workpiece in
cooperation with raising the processing chamber pressure includes
backfilling the processing chamber to said preheating pressure
using the additional process chamber gas input flow from the
backfill reservoir arrangement.
14. The method of claim 13 wherein backfilling includes using a gas
diffuser for introducing the additional process chamber gas input
flow into the processing chamber from said backfill reservoir
arrangement.
15. The method of claim 14 including generating a plasma, as part
of said plasma treatment process, using the process gas, and the
gas diffuser is further used for introducing the process gas into
the processing chamber.
16. The method of claim 13 wherein said backfill reservoir
arrangement is configured to include a backfill reservoir and
storing a backfill gas in the backfill reservoir at a pressure that
is greater than a target pressure to which the processing chamber
is to be backfilled.
17. The method of claim 16 wherein the target pressure is selected
as the preheating pressure for use during heating the workpiece and
heating the workpiece to a treatment temperature for subsequent use
during treating the workpiece.
18. The method of claim 13 including causing a backfill pressure in
the backfill reservoir to rise to a selected value, with the
processing chamber at a treatment pressure that is lower than the
selected value and which treatment pressure is also lower than a
preheating pressure at which the workpiece is to be heated to a
treatment temperature and, thereafter, backfilling includes placing
the backfill reservoir in pressure communication with the
processing chamber in a way which causes the backfill pressure and
the treatment chamber pressure to equalize at least approximately
to the preheating pressure for subsequent use in enhancing a
heating rate of the workpiece.
19. The method of claim 18 wherein said process gas regulation
arrangement provides at least approximately no process gas during
said backfilling.
20. The method of claim 13 wherein said pressure rise rate in the
processing chamber is in a range of approximately 15 to 150 Torr
per second.
21. The method of claim 13 wherein backfilling includes inducing
said pressure rise rate in the processing chamber at approximately
30 Torr per second.
22. The method of claim 1 including simultaneously treating a pair
of workpieces according to steps (a) through (e).
23. The method of claim 1 including processing a series of
workpieces according to steps (a) through (e).
24. In a system for treating at least one workpiece, said system
having at least a transfer chamber and a processing chamber such
that a transfer chamber pressure, in the transfer chamber, and a
processing chamber pressure, in the processing chamber, can each
vary and the workpiece can be moved between the transfer chamber
and the processing chamber, said system further including a process
gas regulation arrangement for providing process gas to said
processing chamber at least during a plasma treatment process at a
given flow rate and which is capable of providing said process gas
at a maximum flow rate, an apparatus comprising: a first
arrangement at least for controlling the processing chamber
pressure to reduce the processing chamber pressure to a treatment
pressure at which the workpiece is to be subjected to a plasma
treatment process and for selectively raising the processing
chamber pressure, in cooperation with said process gas regulation
arrangement, to a preheating pressure, which is higher than the
treatment pressure, at a pressure rise rate resulting at least in
part from using an additional process chamber gas input flow at an
input flow rate which causes an overall input rate to the
processing chamber to be greater than said maximum flow rate,
without raising the transfer chamber pressure; and a second
arrangement in said processing chamber for preheating the workpiece
to a treatment temperature in cooperation with raising the
processing chamber pressure from said treatment pressure to said
preheating pressure, using said first arrangement, and with said
transfer chamber pressure remaining, at least approximately, at
said treatment pressure such that the processing chamber pressure
can then be reduced to the treatment pressure and the workpiece
exposed to said plasma treatment process at least approximately at
said treatment pressure and at said treatment temperature.
25. In a system for treating at least one workpiece, said system
having at least a transfer chamber and a processing chamber such
that a transfer chamber pressure, in the transfer chamber, and a
processing chamber pressure, in the processing chamber, can each be
controlled and the workpiece can be moved between the transfer
chamber and the processing chamber, said system further including a
process gas regulation arrangement for providing process gas to
said processing chamber at least during a plasma treatment process
at a given flow rate and which is otherwise capable of providing
said process gas at a maximum flow rate, a method comprising:
manipulating at least the processing chamber pressure and
cooperatively moving the workpiece between the transfer chamber and
the processing chamber such that the workpiece is exposed to a
preheating pressure in the processing chamber for use in heating
the workpiece to a treatment temperature and so that the workpiece
is subjected to a treatment process in the processing chamber, at
least approximately at a treatment pressure that is lower than the
preheating pressure, after having at least approximately reached
the treatment temperature, in a way which produces a maximum
processing chamber pressure of no more than approximately the
preheating pressure using a value of the preheating pressure that
is less than atmospheric pressure, and using a rate of pressure
increase in the processing chamber from the treatment pressure to
the preheating pressure resulting at least in part from using an
additional process chamber gas input flow at an input flow rate
which causes an overall input rate to the processing chamber to be
greater than said maximum flow rate, without raising the transfer
chamber pressure.
Description
RELATED APPLICATION
[0001] The present application claims priority from U.S.
Provisional Patent Application Ser. No. 60/534,495, filed Jan. 6,
2003, which is incorporated herein by reference in its
entirety.
BACKGROUND OF THE INVENTION
[0002] The present invention is related generally to the field of
processing one or more workpieces and, more particularly, to a
system and method which carries out an overall procedure on
workpieces by using more than one pressure.
[0003] Manufacturing workpieces such as, for example, semiconductor
wafers is often best performed using different pressures at
different points in an overall process. One example of such a
multi-pressure process is described in U.S. Pat. No. 6,409,932
(hereinafter the '932 patent). In particular, at column 2 of the
'932 patent, a seven step prior art process, known as
atmosphere-to-vacuum-to-atmosphere (AVA) processing, is described.
In this process, a wafer is heated to a desired process temperature
in the process chamber, the process chamber is then pumped down to
a desired process pressure, the wafer is subjected to a plasma, the
chamber is vented back to atmospheric pressure and the wafer is
exchanged with another wafer. Such a process is useful, for
example, in removing photoresist from the wafer.
[0004] The '932 patent takes advantage of the well-known principle
that heat transfer efficiency is increased with increased gas
pressure. In attempting to enhance wafer throughput over that which
is available in a prior art AVA system, the '932 patent utilizes an
intermediate pressure at which the wafer is heated in a processing
chamber, after reducing the processing chamber pressure from a
load/unload pressure. The load/unload pressure is not required to
be atmospheric, but is nonetheless higher than the intermediate
pressure. In this regard, it is considered, in view of the
teachings and recognitions of the present invention, that the '932
patent imposes constraints and problems which serve to limit
further enhancement of system throughput.
[0005] It is noted that other prior art has recognized performing
heating at an intermediate pressure in conjunction with using a
transfer chamber. Specifically, the treatment object was
transferred between the transfer chamber and a process chamber at
either the intermediate pressure or the process pressure. It is
recognized herein that required pressure changes in the process
chamber of these prior art systems impose significant limitations
on system throughput, as will be further discussed at an
appropriate point below.
[0006] The present invention is considered to remove the foregoing
constraints and problems while providing still further
advantages.
SUMMARY OF THE DISCLOSURE
[0007] In a system for processing at least one workpiece, an
apparatus and method are described. The system includes at least a
transfer chamber and a processing chamber such that a transfer
chamber pressure, in the transfer chamber, and a processing chamber
pressure, in the processing chamber, can each vary and the
workpiece can be moved between the transfer chamber and the
processing chamber. The system further includes a process gas
regulation arrangement for providing process gas to the processing
chamber at least during a plasma treatment process at a given flow
rate and which is capable of providing the process gas at a maximum
flow rate.
[0008] In one aspect of the present invention, the transfer chamber
pressure and the processing chamber pressure are equalized to a
treatment pressure at which the workpiece is to be subjected to a
plasma treatment process. The workpiece is transferred from the
transfer chamber to the processing chamber at the treatment
pressure. The workpiece is preheated to a treatment temperature, in
cooperation with raising the processing chamber pressure to a
preheating pressure at a pressure rise rate resulting at least in
part from using an additional process chamber gas input flow at an
input flow rate which causes an overall input rate to the
processing chamber to be greater than the maximum flow rate,
without raising the transfer chamber pressure. The processing
chamber pressure is reduced to the treatment pressure. The
workpiece is exposed to the plasma treatment process at least
approximately at the treatment pressure and at the treatment
temperature.
[0009] In another aspect of the present invention, the transfer
chamber pressure and the processing chamber pressure are equalized
to a preheating pressure at which the workpiece is to be heated to
a treatment temperature. In cooperation with equalizing the
transfer chamber pressure and the processing chamber pressure, the
workpiece is transferred from the transfer chamber to the
processing chamber. The workpiece is preheated to a treatment
temperature at the preheating pressure in the processing chamber.
The processing chamber pressure is reduced to the treatment
pressure while the transfer chamber remains at least approximately
at the preheating pressure. The workpiece is exposed to the plasma
treatment process at least approximately at the treatment pressure
and at the treatment temperature. The processing chamber pressure
is then raised to the preheating pressure at a pressure rise rate
resulting at least in part from using an additional process chamber
gas input flow at an input flow rate which causes an overall input
rate to the processing chamber to be greater than the maximum flow
rate, without raising the transfer chamber pressure, for transfer
of the workpiece to the transfer chamber at the preheating
pressure.
[0010] In one implementation, a backfill reservoir arrangement is
configured for selective pressure communication with the processing
chamber for use in selectively backfilling the processing chamber
pressure from the treatment pressure to the preheating
pressure.
[0011] In still another aspect of the present invention, in
pressure isolation from the process chamber, the transfer chamber
pressure is changed to a selected pressure value that is greater
than a preheating pressure at which the workpiece is to be heated
at least approximately to a treatment temperature. With the
processing chamber initially at least approximately at a treatment
pressure, which is lower than the preheating pressure, pressure is
equalized between the transfer chamber and the processing chamber
such that the selected pressure backfills the process chamber at
least approximately to the preheating pressure. In cooperation with
equalizing pressure to the preheating pressure, the workpiece is
moved from the transfer chamber to the processing chamber. The
workpiece is preheated at least approximately to a treatment
temperature at the preheating pressure in the processing chamber.
The processing chamber pressure is reduced to the treatment
pressure in pressure isolation from the transfer chamber pressure.
The workpiece is exposed to the plasma treatment process at least
approximately at the treatment pressure and at the treatment
temperature.
[0012] In yet another aspect of the present invention, at least the
processing chamber pressure is manipulated and the workpiece is
cooperatively moved between the transfer chamber and the processing
chamber such that the workpiece is exposed to a preheating pressure
in the processing chamber for use in enhancing heating of the
workpiece to a treatment temperature and so that the workpiece is
subjected to a treatment process in the processing chamber, at
least approximately at a treatment pressure, that is lower than the
preheating pressure, after having at least approximately reached
the treatment temperature, in a way which produces a maximum
processing chamber pressure of no more than approximately the
preheating pressure, using a value of the preheating pressure that
is less than atmospheric pressure, but greater than the treatment
pressure and using a rate of pressure increase resulting at least
in part from using an additional process chamber gas input flow at
an input flow rate which causes an overall input rate to the
processing chamber to be greater than the maximum flow rate,
without raising the transfer chamber pressure.
[0013] In a continuing aspect of the present invention, for
processing a plurality of workpieces, at least the processing
chamber pressure is manipulated and a first one of the workpieces
is moved between the transfer chamber and the processing chamber
such that the first workpiece is exposed to a preheating pressure
in the processing chamber for use in heating the first workpiece to
a treatment temperature and so that the first workpiece is
subjected to a treatment process in the processing chamber, at
least approximately at a treatment pressure, that is lower than the
preheating pressure, after having at least approximately reached
the treatment temperature, in a way which produces a maximum
processing chamber pressure of no more than approximately the
preheating pressure, using a value of the preheating pressure that
is less than atmospheric pressure, but greater than the treatment
pressure. Workpieces are treated by continuing to manipulate the
transfer chamber pressure, the processing chamber pressure and
cooperatively moving each one of the subsequent ones of the
workpieces between the transfer chamber and the processing chamber
and using a rate of pressure increase resulting at least in part
from using an additional process chamber gas input flow at an input
flow rate which causes an overall input rate to the processing
chamber to be greater than the maximum flow rate, without raising
the transfer chamber pressure. In one feature, multiple workpieces
can be transferred and processed simultaneously.
[0014] In a further aspect of the present invention, a bypass
arrangement is described for selectively providing pressure
communication between the transfer chamber and the processing
chamber for use in producing pressure equalization therebetween,
separate from the use of an isolation valve through which the
workpiece is passed between the transfer chamber and the processing
chamber. In one feature, a control arrangement causes the transfer
chamber pressure to rise to a selected value, with the processing
chamber at a treatment pressure, that is lower than the selected
value and which is also lower than a preheating pressure at which
the workpiece is to be heated to a treatment temperature.
Thereafter, the processing chamber is backfilled by opening at
least the bypass arrangement between the transfer chamber and the
processing chamber in a way which causes the processing chamber
pressure and the treatment chamber pressure to equalize at least
approximately to the preheating pressure for subsequent use in
heating the workpiece. In another feature, the bypass arrangement
serves to selectively provide pressure communication between the
transfer chamber and the processing chamber for use in pressure
equalization therebetween without a need to use the isolation
valve.
[0015] In another implementation, in a system for treating at least
one workpiece in accordance with a multi-step overall process which
preheats the workpiece in a processing chamber to a treatment
temperature at a preheating pressure and, thereafter, exposes the
workpiece to a plasma at a treatment pressure in the processing
chamber and at least approximately at the treatment temperature,
the treatment pressure being less than the preheating pressure such
that the processing chamber pressure must be raised from the
treatment pressure at least to the preheating pressure at one or
more points during the multi-step overall process. The system
further includes a process gas regulation arrangement for providing
process gas to the processing chamber at least during exposing the
workpiece to the plasma at a given flow rate and which is capable
of providing the process gas at a maximum flow rate, an arrangement
is provided for use in raising the processing chamber pressure from
the treatment pressure at least to the preheating pressure at the
one or more points during the multi-step overall process by
providing an additional process chamber gas input flow at an input
flow rate which causes an overall input rate to the processing
chamber to be greater than the maximum flow rate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The present invention may be understood by reference to the
following detailed description taken in conjunction with the
drawings briefly described below.
[0017] FIG. 1A is a diagrammatic cut-away view, in elevation, of a
workpiece handling system, produced in accordance with the present
invention and in which a backfill arrangement is provided to induce
a rapid pressure rise in the process chamber.
[0018] FIG. 1B is a diagrammatic cut-away view, in elevation, of
another embodiment of a workpiece handling system, produced in
accordance with the present invention, in which bypass arrangement
is provided for use in backfilling the process chamber from the
transfer chamber.
[0019] FIG. 2 is a flow diagram illustrating one manner in which
the system of FIG. 1A can be used in which the transfer chamber
remains, at least approximately, at a treatment pressure to which
the workpiece is to be exposed during plasma treatment in the
process chamber.
[0020] FIG. 3 is a plot illustrating processing chamber pressure,
backfill chamber pressure and workpiece temperature against time,
based on the flow diagram of FIG. 2.
[0021] FIG. 4 is a flow diagram illustrating one manner in which
the system of FIG. 1A can be used in which the transfer chamber
remains, at least approximately, at a preheating pressure to which
the workpiece is exposed in the processing chamber to enhance
workpiece heating.
[0022] FIG. 5 is a plot illustrating processing chamber pressure,
backfill chamber pressure and workpiece temperature against time,
based on the flow diagrams of FIG. 4.
[0023] FIG. 6 is a flow diagram illustrating one manner in which
the system of FIG. 1B can be used such that the transfer chamber
backfills the process chamber from the treatment pressure to the
preheating pressure.
[0024] FIG. 7 is diagrammatic cut-away view, in elevation, of still
another embodiment of a workpiece handling system, produced in
accordance with the present invention, in which dual processing
stations are provided along with a bypass arrangement and backfill
arrangement, either or both of which can be used to backfill the
process chamber.
DETAILED DESCRIPTION
[0025] The following description is presented to enable one of
ordinary skill in the art to make and use the invention and is
provided in the context of a patent application and its
requirements. Various modifications to the described embodiments
will be readily apparent to those skilled in the art and the
generic principles herein may be applied to other embodiments.
Thus, the present invention is not intended to be limited to the
embodiment shown but is to be accorded the widest scope consistent
with the principles and features described herein. It is noted that
the drawings are not to scale and are diagrammatic in nature.
[0026] FIG. 1A is a diagrammatic view, in elevation, of a
semiconductor workpiece processing system, generally indicated by
the reference number 10, according to one embodiment of the present
invention. While system 10 represents one system which is useful in
the practice of the present invention, it is to be understood that
the present invention may be utilized in conjunction with a variety
of system configurations and the presently illustrated
implementation is not intended as being limiting. As will be seen,
the present invention may be practiced using any system having at
least having appropriate selective and separate pressure variation
capabilities at least in its processing chamber. Of course, there
must be a provision for transferring workpieces between the
transfer and processing chambers. The system may be configured to
accommodate many alternative features which are compatible with the
practice of the present invention and which are typically
associated with high throughput platforms including, for example,
the use of one or more workpiece cassettes, dual workpiece
processing positions in its processing chamber, and one or more
load locks. U.S. Pat. No. 6,315,512 serves as one example in which
such features are described and is incorporated herein by reference
in its entirety. It is considered that one of ordinary skill in the
art may readily adapt a system having such features for use in the
practice of the present invention in view of the overall disclosure
of the present application. It is noted that like reference numbers
have been applied to like items, when possible, throughout this
disclosure.
[0027] With continuing reference to FIG. 1A, system 10 includes a
transfer chamber 12, which is only partially shown, having a robot
14 positioned therein. Robot 14 includes an arm 18 and an end
effector (paddle) 20 which is moved by arm 18. For purposes of the
present example, system 10 will be described in the context of
removing a photoresist layer or pattern 22 (greatly exaggerated in
thickness) from a semiconductor workpiece 30, although one of
ordinary skill in the art will appreciate that this system is
readily useful in the application of other processes including, but
not limited to various implementations of chemical vapor
deposition, atomic layer deposition and plasma etch, wherein the
workpiece is subjected to different pressures at different process
points. Accordingly, for purposes of the present example, a
plasma-processing chamber 32 is provided having a plasma source 34
such as, for example, an inductively coupled plasma (ICP) source.
Plasma source 34 is used to generate a plasma 36 that is suitable
for use in photoresist removal. Other suitable plasma sources
include, but are not limited to microwave sources, surface wave
plasma sources, ECR plasma sources, capacitively coupled (parallel
plate) plasma sources. It is noted that the terms "processing
chamber" or "process chamber" may refer to an arrangement for
housing a workpiece in conjunction with a treatment source such as,
for example, a plasma source.
[0028] Plasma chamber 34 may be used to implement plasmas in an
exemplary process window such as, for example:
[0029] Process Pressure: 0.2 to 20 Torr (approximately 1 Torr has
been found as useful)
[0030] Plasma RF Power (per workpiece): 500 to 5,000 W
(approximately 3,000 W has been found as useful)
[0031] Process Gas(es): some combination or all of the following
gases:
[0032] O.sub.2 Flow: 1,000-20,000 (5,000-10,000 sccm has been found
as useful)
[0033] Ar, He, N.sub.2 Flow: Separate or combined 50-5000 sccm (500
sccm has been found as useful)
[0034] H.sub.2, D.sub.2, HD Flow: Separate or combined 1,000-20,000
sccm (approximately 10,000 sccm has been found as useful)
[0035] Forming Gas (4-10% H.sub.2-- balance N.sub.2): 1,000-15,000
sccm (approximately 10,000 sccm has been found to be useful)
[0036] Hydrocarbon Gas (low molecular wt.): Such as CH.sub.4,
C.sub.2H.sub.4, C.sub.2H.sub.6, C.sub.3H.sub.8, C.sub.4H.sub.10,
etc.)--Flow 1,000-10,000 sccm (CH.sub.4 with a flow of
approximately 5,000 sccm has been found to be useful)
[0037] Halocarbon Containing Gas: Such as CF.sub.4, C.sub.2F.sub.6,
C.sub.3F.sub.8, C.sub.4F.sub.6, c-C.sub.4F.sub.8, CHF.sub.3,
CH.sub.2F.sub.2, CH.sub.3F, C.sub.2HF.sub.5, C.sub.2H.sub.2F.sub.4,
ClCF.sub.3, Cl.sub.2CF.sub.2, etc.--Flow less than approximately
300 sccm
[0038] HF Flow: less than approximately 300 sccm
[0039] N.sub.2O Flow: 50-5000 sccm
[0040] NH.sub.3 Flow: 50-5000 sccm.
[0041] In the dry process removal of photoresist, it is known that
the removal rate of the photoresist increases with increases in the
temperature of the workpiece during plasma exposure. For example,
heating the workpiece to a temperature in a range extending from
approximately 150 C.degree. to 350 C.degree. is contemplated in
order to reach higher workpiece throughput.
[0042] Continuing with the description of FIG. 1A, workpiece 30 is
supported on a susceptor 38. The susceptor is useful in heating the
workpiece to the desired temperature. Due to constraints in raising
the temperature of the susceptor, it has been found to be practical
to maintain the susceptor at a fixed temperature throughout the
entire process cycle. Alternatively, the susceptor can at least be
preheated prior to a process cycle. The susceptor may be maintained
or preheated to a temperature at or between 90.degree. C. and
400.degree. C. Approximately, 300C.degree. has been found to be
useful, although lower values may be used in order to accommodate
additional heating, resulting from plasma exposure and/or
material/device thermal constraints. Any suitable form of susceptor
may be used such as, for example, a suitable platen. Lift pins 50
are used in cooperation with robot 14 for purposes of moving
workpiece 30 whereby the lift pins are used to position and move
(not shown) the workpiece above end effector 20 and susceptor 38,
as needed. The lift pins are shown in a retracted position and
end-effector 20 is shown withdrawn into transfer chamber 12 such
that workpiece 30 is supported on susceptor 38. A through passage
42 is defined between transfer chamber 12 and processing chamber 32
such that robot 14 can transfer workpieces therethrough. An
isolation valve 44 such as, for example, a vacuum isolation gate
valve or slit valve is used to selectively close passage 42 either
completely or partially (in the instance, for example, of providing
pressure communication for equalization purposes between the two
chambers). In the present example, valve 44 is opened using
compound motion in directions that are indicated by an arrow 45
having a right turn in its shaft. An exhaust port 46 is used in
producing a vacuum in the process chamber, in cooperation with an
appropriate configuration. Exhaust gas 48 flows in a direction
indicated by an arrow.
[0043] Plasma chamber or module 34 includes a gas diffuser 50 which
receives inputs from a process gas input 52 and a backfill
arrangement 54. The latter provides an input to diffuser 50 at a
backfill input 56. It is noted that inputs 52 can be connected to
one another in a "T" configuration so as to share a single gas
input in order to avoid a need for the dual input diffuser 50. The
term "backfill" is used to describe bringing a lower pressure to a
higher pressure, as a result of communication with an initially
higher pressure. It is noted that the diffuser has been designed to
evenly distribute the pressure in plasma source 34 and to minimize
the possibility of plasma flowing back into gas diffuser 50, and
the gas inlet lines 52 and 56. Process gases 58 generally comprise
the gas mixtures that are used for plasma generation, although
gases may also be introduced, via process gas input 52, for
purposes of enhancing temperature ramping of workpiece 30. In this
regard, the process gases are regulated by an MFC (Mass Flow
Controller) 60 which is provided for the purpose of regulating the
input of process gases with a high degree of precision during
actual exposure of the workpiece to plasma so as to control the
characteristics of the plasma. While the MFC provides such precise
control, the flow rate is quite low. Further, devices such as this
MFC are characterized by a maximum flow value that is typically
quite low. Hence, it is recognized that a significant limitation is
imposed with respect to inflow by relying solely on the MFC.
Backfill input 56 leads to a backfill valve 66 which is, in turn,
connected to a backfill ballast chamber 68. Details with respect to
the volume and operation of backfill arrangement 54 will be
provided below. For the moment, it is sufficient to note that
backfill input 56, valve 66, backfill chamber 68 and all associated
piping should be configured to facilitate a rapid pressure rise in
processing chamber 32, for example, from a low, plasma treatment
pressure to a higher workpiece preheating pressure either alone or
in cooperation with process gas input 52. A backfill chamber line
70 leads from a backfill supply valve 72 to backfill chamber 68. An
appropriate supply line 74 is connected to an input of backfill
supply valve 72. Backfill gas 76 is indicated by an arrow. Pressure
in backfill chamber 68 is monitored using a pressure sensor 78. In
this way, a specified starting pressure in the backfill chamber can
be achieved prior to the initiation of process chamber backfill in
cooperation with the use of supply valve 72. Alternatively, to
ensure a controlled pressure condition in the backfill chamber, a
mass flow controller (not shown) can be used to meter gas into the
backfill chamber over known time periods. It is considered that one
having ordinary skill in the art can readily implement this
backfill arrangement in view of this overall disclosure. A gas
diffuser 79 is positioned between plasma chamber 34 and processing
chamber 32 for purposes of enhancing process uniformity, however,
the gas diffuser is not a requirement.
[0044] Using backfill arrangement 54, either alone or in
cooperation with process gas MFC 60, it is considered processing
chamber rise rates of more than 15 Torr per second can be produced.
Even rise rates of 150 Torr per second or more are considered as
practical.
[0045] Attention is now directed to FIG. 1B which diagrammatically
illustrates a modified system implementation that is generally
indicated by the reference number 80. System 80 resembles system 10
of FIG. 1A, with the exception that backfill arrangement 54 is not
required and a single input gas diffuser (not shown) is used.
Further, a pressure bypass arrangement 82 is illustrated for
selectively providing pressure communication between transfer
chamber 12 and processing chamber 32. Bypass arrangement 82
includes piping 84 and a bypass valve 86. The latter can be opened
in any suitable manner for accomplishing a desired pressure profile
equalization between the processing and transfer chambers. All
components of bypass arrangement 82 can be sized so as to allow for
implementing rapid pressure equalization between the two chambers
at a rate of at least 15 Torr per second. Rates of 150 Torr per
second or more are considered as practical. Accordingly, a
transition from less than 1 Torr to 60 Torr can be executed, as a
low-end performance limit, in less than 4 seconds. Of course, far
shorter transition times are contemplated with less than 2 seconds
having already been demonstrated for the same pressure change.
Control of systems 10 and 80 can readily be accomplished by one
having ordinary skill in the art and in view of this overall
disclosure, for example, using a computer 90 and suitable pressure
and/or gas flow control sensors in a way which provides for
implementing all procedures contemplated herein. Another difference
in system 80 resides in the provision of an MFC 92 having an input
94 which is connected to a suitable gas supply and an output 96
which feeds into transfer chamber 12. The purpose of MFC 92 will be
described below. It is noted that pressure in transfer chamber 12
can be controlled in alternative ways. As non-limiting examples, a
pressure sensor can be used in combination with one of a gas flow
shut-off valve or a throttle valve in pressure communication with
the transfer chamber.
[0046] Turning now to FIGS. 2 and 3 in conjunction with FIG. 1A, a
first mode in which system 10 may be used will now be described.
FIG. 2 is a flow diagram illustrating the various steps of this
mode, generally indicated by the reference number 100, while FIG. 3
is a plot of processing chamber pressure and workpiece temperature
versus time. It is noted with respect to all of the plots described
herein, including that of FIG. 3, that while specific time,
pressure and temperature values are illustrated, such values are in
no way intended as limiting, but are exemplary in nature. FIG. 2,
as well as other figures described below, may refer to the process
chamber as "PC" and the transfer chamber as "TC". Photoresist may
be referred to as "PR". In FIG. 3, a first plot 101a illustrates
process chamber 32 pressure against time, a second plot 101b
illustrates backfill chamber 68 pressure against time and a third
plot 102 illustrates workpiece temperature against time. In this
mode, transfer chamber 12 is operated at approximately the same low
pressure that is used for plasma exposure of workpiece 30 and
photoresist 22 thereon. This pressure may be referred to herein as
a treatment pressure and is indicated as P.sub.0 in FIG. 3. The
treatment pressure may be a range from approximately 0.01 to 10
Torr and can be approximately 1 Torr. Initially, a workpiece is
moved from transfer chamber 12 to processing chamber 32 and
positioned on susceptor 38. To that end, isolation/gate valve 44 is
opened (as indicated by arrow 56) between the two chambers, if not
already opened. In relation to the isolation/gate valve being
opened, lift-pins 40 are extended above the top surface of the
susceptor (if not already in the raised/extended position). Also in
relation to the isolation/gate valve being opened, a workpiece is
inserted into the process chamber supported by end-effector 20
attached to robotic arm 18. After the workpiece comes to a desired
location above the lift pins, the end-effector lowers the workpiece
(z-axis control of the robotic arm connected to the end-effector)
onto the lift-pins. After depositing the workpiece onto the top of
the lift-pins, the robotic arm extracts end-effector 20 from the
process chamber. In time relation to the end-effector being
completely extracted from the process chamber, the isolation/gate
valve 44 is closed. The foregoing steps should be familiar to one
having ordinary skill in the art in accomplishing moving the
workpiece to a treatment position.
[0047] Having described initial workpiece positioning, in step 103
of mode 100, the workpiece is lowered to its treatment position
onto susceptor 38 by retracting lift pins 40, as is the case in
FIG. 1. The workpiece temperature is approximately T.sub.0 (see
FIG. 3), at a time t.sub.0, prior to heating. Since the susceptor
is already hot, workpiece temperature starts to rise from T.sub.0
as soon as the workpiece is in the proximity of the heated
susceptor, with the susceptor heated to between approximately
150C.degree. and approximately 350C.degree.. The workpiece
temperature rise is attributable to radiation, gas convection and
conduction thermal transfer processes. In relation to the workpiece
coming to rest on the susceptor, the pressure in process chamber 32
and, hence, plasma chamber 34, is raised rapidly from P.sub.0 in
FIG. 3 to a preheating pressure P.sub.1 which can be in a range
from approximately 25 Torr to 250 Torr by the addition of gas/gases
that can be optimized for rapid workpiece heat-up rate. A very
rapid pressure rise, such as depicted in FIG. 3 from P.sub.0 to
P.sub.1, can be produced by using backfill arrangement 54 in the
interval from time t.sub.0 to t.sub.1. It is contemplated that a
preheating pressure of approximately 60 Torr is adequate and that,
at this pressure, most of the benefit from improved heating rate,
which could be derived from a higher pressure, is realized. That
is, raising the pressure significantly higher than 60 Torr requires
additional time, as well as additional time to later reduce the
pressure, thereby decreasing throughput. Such a rapid increase in
pressure within the process chamber is accomplished by opening
backfill valve 66 so as to release pressurized gas, which is stored
at higher pressure, from backfill reservoir 68. It is noted that
the backfill reservoir is typically in close proximity to the
process chamber. In this regard, reservoir 68 is sized to
accommodate an adequate volume of gas at an adequate pressure to
bring the process/plasma chamber combination to the desired
pressure. It is worthwhile to note, with respect to all embodiments
described herein, that minimizing process chamber gas volume
contributes directly enhances the rate of pressure rise that can be
achieved.
[0048] There are at least two ways in which the rapid pressure rise
can be performed. FIG. 3 illustrates a backfill equalization
technique wherein the backfill pressure is previously raised or set
to a selected pressure value P.sub.sel (see plot 101b at t.sub.0).
This pressure value is selected based, in part, on the volumes of
the backfill chamber and process chamber such that the two chambers
equalize to preheating pressure P.sub.1 at t.sub.1, subsequent to
opening backfill valve 66 at t.sub.0. That is, plots 101a and 101b
merge at t.sub.1. Backfill valve 66 is closed following
equalization and the backfill chamber pressure (plot 101b) is
caused to rise to P.sub.sel from approximately t.sub.3 to t.sub.5.
While P.sub.sel is shown as 65 Torr for purposes of illustrative
convenience, it is to be understood that this value can be
determined in a number of ways, as will be described below, and the
use of this value is not intended as being limiting. As an
alternative technique which is not plotted in FIG. 3, but which is
readily understood in view of FIG. 1A, the backfill chamber
pressure can be raised to a significantly higher value than
P.sub.sel such that the backfill chamber always remains higher than
P.sub.1. In order to terminate the backfill when the process
chamber reaches P.sub.1, backfill valve 66 is closed. That is, once
the process chamber pressure rises to the preheating pressure,
backfill valve 66 is closed. As part of either technique, supply
valve 72 may be opened, with backfill valve 66 closed, to replenish
backfill reservoir 68 to a desired pressure. Depending on various
factors including chamber volumes and flow rates, the latter,
alternative technique may produce a more rapid pressure rise. Using
either technique, however, a rapid pressure increase in the process
chamber can be produced, as needed in the overall processing
scheme. It is noted that either of these techniques can be used at
any time in the context of an overall processing scheme when it is
desired to induce a pressure rise in process chamber 32 using
backfill chamber 68. In an actual implementation, a flow rate of
approximately 30 Torr/second was accomplished. Pressure rise rates
from about 15 Torr to more than 150 Torr/second are considered to
be useful.
[0049] At step 104, once the workpiece temperature approaches the
susceptor temperature (but typically is slightly less than the
susceptor temperature), the pressure in the process chamber is
reduced quickly to a treatment pressure that is required for the
photoresist plasma etch step. FIG. 3 illustrates that pressure
P.sub.1 is maintained from time t.sub.1 to time t.sub.2. At time
t.sub.2, however, the process chamber pressure is rapidly decreased
so as to begin to return to P.sub.0. Treatment pressure P.sub.0 for
the plasma exposure step may be in a pressure range extending from
approximately 0.01 to 10 Torr. The treatment pressure is reached at
t.sub.3. Also, as the workpiece temperature approaches or is in
some desired relationship with the susceptor temperature such as,
for example, being slightly below the susceptor temperature, plasma
gas flow initiation is performed in process chamber 32. Plasma gas
58 then flows into diffuser 50 and into plasma chamber 34. This may
take place, for example, in a time range comprising at least a
portion of the interval between and including t.sub.2 and t.sub.4.
It is noted that triggering of process steps, as described in terms
of reaching either temperature or pressure values, may be
responsive to a measured value, may utilize fixed time periods
based on previous system performance determinations or may
represent a combination of both.
[0050] In step 106, in relation to the processing chamber reaching
the desired treatment pressure for the plasma etch step and having
introduced the plasma gas supply, an RF power supply and matching
network (not shown) associated with plasma chamber 34 are turned on
at t.sub.4 and the matching network starts to tune to a point at
which a stable plasma will ignite and the plasma etch process
begins. FIG. 3 illustrates a ten second plasma etch which concludes
at time t.sub.5. It can be seen that the workpiece temperature
rises somewhat from t.sub.4 to t.sub.5 with ongoing exposure to the
plasma. The workpiece temperature rise resulting from exposure to
the plasma can be minimized by use of an electrostatic clamping
arrangement incorporated into susceptor 38.
[0051] In relation to termination of the plasma etch process at
t.sub.5 in step 108, the gases used for plasma generation, passing
through the process chamber, are discontinued. The pressure of the
process chamber and the workpiece transfer chamber may be
equalized, if needed, to the treatment pressure and isolation/gate
valve 44, between the process chamber and the transfer chamber, is
opened. The lift pins are extended and the workpiece is raised
above the top surface of the susceptor.
[0052] In step 110, so long as both valve 44 is open and lift-pins
40 are extended, end-effector 20 may be extended into the process
chamber and the workpiece transferred back to transfer chamber
12.
[0053] Step 112 then transfers another workpiece into the treatment
chamber and the process repeats as described above.
[0054] The gaseous environment used for achieving a rapid workpiece
heat-up rate consist of one or more of the following gases (the
exact combination and ratio will depend on the required workpiece
heat-up rate: Ar, He, H.sub.2, D.sub.2, HD, HF, O.sub.2, N.sub.2,
NH.sub.3, N.sub.2O, a low molecular weight hydrocarbon gas (such as
CH.sub.4, C.sub.2H.sub.4, C.sub.2H.sub.6, C.sub.3H.sub.8,
C.sub.4H.sub.10, etc.), a halocarbon containing gas (such as
CF.sub.4, C.sub.2F.sub.6, C.sub.3F.sub.8, C.sub.4F.sub.6,
c-C.sub.4F.sub.8, CHF.sub.3, CH.sub.2F.sub.2, CH.sub.3F,
C.sub.2HF.sub.5, C.sub.2H.sub.2F.sub.4, ClCF.sub.3,
Cl.sub.2CF.sub.2, etc.). The specific gaseous environment can be
optimized for rapid workpiece heat-up and/or cooling rate. This gas
mixture may be referred to herein as "preheating gas." One benefit
of this processing scheme is to decrease the time required to
process workpieces and thereby increase the number of workpieces
per hour that can be processed. It should be appreciated that the
use of the preheating gas is intended to shorten time intervals
shown in the drawings with respect to heating of the workpiece and
may be used to enhance cooling intervals, as will be described
below.
[0055] Turning now to FIGS. 4 and 5 in conjunction with FIG. 1A, a
second mode in which system 10 may be used will now be described.
FIG. 4 is a flow diagram illustrating the various steps of this
mode, generally indicated by the reference number 200, while FIG. 3
is a plot of processing chamber pressure, backfill chamber pressure
and workpiece temperature versus time. A plot 202a illustrates
process chamber 32 pressure against time, a plot 202b illustrates
backfill chamber 68 pressure against time and a plot 204
illustrates workpiece temperature against time. In this second
mode, transfer chamber 12 is operated essentially continuously at
approximately preheating pressure P.sub.1, which is used in the
processing chamber during workpiece heating prior to plasma
exposure at pressure P.sub.0. It is noted that certain aspects of
the second mode, already described above such as, for example, the
use of lift pins 40 in concert with effector arm 20 and isolation
valve 44 may not be repeated for purposes of brevity. Moreover, it
is to be understood that these components may be operated in many
modified, but equivalent ways and in a coordinated manner with
respect to one another, while still accomplishing the intended
objective of moving a workpiece between the transfer and processing
chambers. Further aspects with respect to operation of lift-pins
40, in the context of the present invention, will be described
below.
[0056] Initially, step 206 moves a workpiece 30 from transfer
chamber 12 to processing chamber 32 and positions the workpiece on
susceptor 38. Since the processing chamber is already at the
preheating pressure, the workpiece will experience an enhanced
heating effect as it is brought into proximity to susceptor 38 and
then lowered onto the susceptor. Thus, workpiece temperature rises
from T.sub.0 at time t.sub.0 to T.sub.2 at time t.sub.2.
[0057] In step 208, in relation to the workpiece reaching the
treatment temperature, T.sub.2, at time t.sub.2, pressure is
reduced in processing chamber 32 from P.sub.1 to treatment pressure
P.sub.0, which is achieved, in the present example, at t.sub.3. It
is noted that the aforedescribed preheating gas mixture, if
employed, may be used in both the transfer chamber and in the
processing chamber, for convenience as well as for reasons yet to
be described. Otherwise, these gases are appropriately introduced,
via diffuser 50, into the processing chamber for purposes of
accomplishing preheating of the workpiece so as to enhance the rate
of temperature rise from t.sub.0 to t.sub.2, in a way which
shortens this time interval.
[0058] Plasma exposure is initiated at t.sub.4, in step 210, after
the introduction of plasma gases into the process chamber and
plasma ignition, with processing chamber 32 at P.sub.0. Plasma
exposure continues to time t.sub.5. Plasma gas introduction is then
terminated.
[0059] Step 212 accomplishes raising process chamber pressure to
P.sub.1, which may be performed using the preheating gas mixture,
and lifting the workpiece from susceptor 38. A rapid pressure
increase, as depicted, can be accomplished using backfill
arrangement 54, as described above. It is noted that a pressure
rise from P.sub.0 to P.sub.1 is induced from t.sub.5 to t.sub.6 in
process chamber pressure plot 202a with a resultant drop in
backfill chamber pressure plot 202b over this time period.
Following this drop in backfill chamber pressure, with backfill
valve 66 closed, P.sub.sel or a higher desired pressure can be
restored in the backfill chamber as shown by plot 202b prior to
t.sub.5. Again, the backfill chamber pressure can be raised to a
significantly higher value than P.sub.sel such that the backfill
chamber always remains higher than P.sub.1. In this case, the
primary differences in backfill chamber pressure plot 202b reside
in raising the high pressure above P.sub.sel as well as providing a
steeper, more linear pressure rise from P.sub.0 to P.sub.1, as well
as a steeper more linear drop in plot 202b from P.sub.sel to
P.sub.1. Further, at t.sub.6, plots 202a and 202b will not merge
asymptotically, but will more closely resemble linear sloped
functions. Moreover, the backfill arrangement can be used to
introduce the preheating gas mixture or can be customized to mix
with other gases in the process chamber so as to produce a desired
gas mixture.
[0060] The workpiece is then transferred by step 214 from
processing chamber 32 to transfer chamber 12 at approximately the
preheating pressure. It is noted that cooling of the workpiece will
be enhanced as a result of its exposure to the preheating pressure,
subsequent to plasma exposure and during its return trip to the
transfer chamber. It is estimated that the workpiece may cool, in
this manner, by as much as at least 30 additional degrees
centigrade, prior to exiting transfer chamber 12. This cooling
effect may be enhanced even further with the use of the preheating
gas mixture in one or both of the transfer and process chambers.
Thus, the "preheating" gas pressure and mixture are each seen to be
advantageous in cooling the workpiece as well as in heating it. It
should be appreciated that a great degree of flexibility is
provided with respect to workpiece cooling. Through the selection
of the preheating pressure, the rate of cooling of the workpiece
can be customized such that the workpiece cools in a desired way as
it travels through and exits the transfer chamber. Further,
selection of cooling gas mixture provides an opportunity for even
greater customization of the cooling parameters.
[0061] With both transfer chamber 12 and processing chamber 32 at
the preheating pressure, another workpiece can be transferred (step
216) into the process chamber and the foregoing sequence
repeated.
[0062] Referring to FIGS. 5 and 6, a third mode will now be
described in which system 80 of FIG. 1B can be used. In the third
mode, transfer chamber 12 is pressurized, in isolation from process
chamber 32, so as to reach a selected pressure value, P.sub.sel,
that is higher than preheating pressure P.sub.1 at certain points
in the overall operation. MFC 92 is provided for raising the
transfer chamber pressure to the selected pressure value. It is
noted that the pressure profiles of the third mode, with respect to
the process chamber, are essentially identical in appearance to
that of the second mode and, hence, to the appearance of plots 202a
and 202b of FIG. 5. That is, the process chamber pressure is
represented by plot 202a, while the transfer chamber pressure is
represented by plot 202b, as will be further described. FIG. 6
illustrates the various steps which make up the third mode,
generally indicated by the reference number 300. It is again noted
that certain aspects of the modes, already described above such as,
for example, the use of lift pins 40 in concert with effector-arm
20 and isolation valve 44 may not be repeated for purposes of
brevity.
[0063] Referring again to FIG. 1B, the spirit of this third mode is
to use the selected pressure value in the transfer chamber in a way
which backfills process chamber 32 so as to cause the process
chamber and the transfer chamber to equalize, at least
approximately, to the preheating pressure. That is, the process
chamber pressure rises from treatment pressure P.sub.0 to
preheating pressure P.sub.1 while transfer chamber 12 pressure
drops from selected pressure P.sub.sel to preheating pressure
P.sub.1. Because backfill chamber 68 of FIG. 1A can be used in this
manner, as is described above, determinations of selected pressure
values with respect to the transfer chamber are equally applicable
to determinations of backfill chamber selected pressure when used
in the aforedescribed backfill technique. An appropriate value for
the selected pressure can be determined at least to a useful
approximation, if the pressure used for preheating is much higher
than the pressure used for plasma treatment (i.e.,
P.sub.1>>P.sub.0), for example, based on Boyle's Law for an
idealized gas, written as:
P.sub.SelV.sub.tc=P.sub.1V.sub.tot (1)
[0064] Where P.sub.sel is the selected pressure value to be
determined and P.sub.1 is the preheating pressure, V.sub.tc is the
volume of the transfer chamber and V.sub.tot is the combined volume
of the transfer chamber and the process chamber. It is noted that
any contribution from the initial pressure (i.e., the treatment
pressure) in the processing chamber has been ignored for purposes
of simplicity since, for example, at 1 Torr, it is much less than
the selected pressure value. Of course, the selected pressure value
may readily be determined and/or fine-tuned empirically by one
having ordinary skill in the art.
[0065] As exemplary values, the transfer chamber can be maintained
at a pressure from approximately 25 to 250 Torr with approximately
65 Torr as a potential selected pressure. The process chamber is
maintained at the treatment pressure required for the desired
plasma process in the range of 0.01 to 10 Torr with 1 Torr as a
typical pressure. The difference in the respective pressures is
such that, for example, to raise the pressure in the process
chamber, during the rapid heating process, to approximately 60 Torr
and if the ratio of the volume of the gaseous environments is such
that the transfer chamber is approximately 10.times. that of the
process chamber, one can set the pressure of the transfer chamber
to approximately 65 Torr, so that when the isolation/gate valve
between the transfer chamber and the process chamber is opened, the
pressure in both chambers equalizes at a pressure of approximately
60 Torr. Of course, different ratios in the respective gaseous
environments of both chambers and a different preheating pressure
for the rapid workpiece heating cycle in the process chamber
necessitate setting the transfer chamber at a different selected
pressure. The higher selected pressure and the larger volume of the
gaseous environment of the transfer chamber is used to "rapidly"
raise the pressure in the process chamber to the desired preheating
pressure for rapid heat-up of the workpiece. Of course, this
discussion is equally applicable with respect to the use of
backfill chamber 68 of FIG. 1 in the backfill equalization
technique described above.
[0066] Referring to FIGS. 1B and 5, consistent with ongoing
processing of a plurality of workpieces, as will be seen, it will
initially be assumed in step 304 that transfer chamber 12 and
processing chamber 32 are equalized to preheating pressure P.sub.1
and that a workpiece is in the treatment position in the processing
chamber. Accordingly, isolation valve 44 and bypass valve 86 can
both be closed and workpiece 30 heats from T.sub.0 at time t.sub.0
to preheating temperature T.sub.2 at time t.sub.2.
[0067] Moving to step 306, once the valves are closed, treatment
chamber 12 is returned to selected pressure P.sub.sel. It is again
noted that a plot of transfer chamber pressure may resemble the
appearance of backfill chamber plot 202b of FIG. 5. It is
considered that these plots will be identical, at least from a
practical standpoint, if the backfill chamber volume and transfer
chamber volume and flow rates are approximately identical, although
this is not required and many modifications may be made by one
having ordinary skill in the art in view of this overall
disclosure. For purposes of brevity, however, it will be assumed
that plot 202b of FIG. 5 represents the variation of transfer
chamber pressure over time. Accordingly, beginning shortly after to
and using MFC 92, transfer chamber pressure rises to P.sub.sel. It
should be appreciated that this re-pressurization may be performed
at any suitable rate and starting at any appropriate time, so long
as the transfer chamber reaches the selected pressure value prior
to a subsequent need to raise process chamber from the treatment
pressure to the preheating pressure.
[0068] In time relation to the workpiece reaching the treatment
temperature, plot 202a of FIG. 5 illustrates a reduction in process
chamber pressure (step 308) from P.sub.1 at t.sub.2 to P.sub.0 at
t.sub.3. This reduction in pressure is accomplished by evacuation,
responsive to vacuum pumping, at an appropriate port which is not
illustrated in the present figure, but can be represented by
exhaust port 46 of FIG. 1A.
[0069] In time relation to processing chamber 32 reaching P.sub.0,
photoresist strip can be initiated in step 310 with an introduction
of plasma gases and striking the plasma, as described above. The
strip interval runs until time t.sub.5 in FIG. 5.
[0070] In step 312, in time relation to termination of the PR strip
interval, accompanied by termination of plasma gas flow, processing
chamber 32 is backfilled from transfer chamber 12 so as to produce
a rapid increase in process chamber pressure plot 202a from the
treatment pressure to the preheating pressure. This pressure rise
starts at time t.sub.5 and the preheating pressure is achieved at
t.sub.6. The pressure rise in process chamber pressure plot 202a is
produced responsive to a drop in transfer chamber pressure plot
202b from P.sub.sel to P.sub.1 which occurs from t.sub.5 to
t.sub.6, respectively. It should be appreciated that, in order to
achieve this rate of pressure increase, system 80 must accommodate
a relatively large, but short duration of gas flow during the
backfill. Bypass arrangement 82, of FIG. 1B, is specifically
configured for this purpose. That is, ports, piping 84 and bypass
valve 86 are all sized to cooperatively provide for this rate of
flow. A large diameter pipe should be used, while ensuring that the
pipe length, including any valves in between, do not present any
constrictions that can choke gas flow. It is considered that one of
ordinary skill in the art is capable of implementing the bypass
arrangement in terms of porting and piping with this disclosure in
hand. Specific values of flow rates will depend, of course, on the
relative volumes of the transfer chamber and process chamber.
Pressure rise rates, in the process chamber, comparable or greater
than those available using the backfill chamber arrangement of FIG.
1A are considered to be achievable, since high conductance piping
and components can be used. It is noted that the bypass arrangement
port locations as well as vacuum pumping port locations that are
shown in the various figures are diagrammatic in nature and are not
intended as being limiting. Moreover, the bypass arrangement may be
considered as optional. That is, isolation valve 44 can be
configured to accommodate the contemplated flow rates. As still
another alternative, the bypass arrangement and isolation valve can
be used in combination to provide a distribution of the backfill
flow. It is noted that consideration should be given to avoiding
introduction and/or disturbance of particles which could be present
in the transfer and/or process chambers, as a result of a large
flow rate during this backfill step, as well as during any other
high flow rate steps. Accordingly, port locations, dimensions
and/or orientations can be configured with this in mind.
[0071] The treated workpiece is removed from process chamber 32, in
step 314, and another workpiece is moved from the transfer chamber
to the treatment position in process chamber 32.
[0072] Referring to FIGS. 1A and 1B, having described a number of
modes in which representative systems 10 and 80 can be operated,
further aspects with respect to the operation of lift-pins 40 will
now be described. It should be appreciated that preheating can be
accomplished with the lift-pins up, down or in a suitable
combination. Such combinations include, for example, (i) a
combination of first pins-up followed by pins-down, (ii) a
combination of pins-up followed by pins-down followed by pins-up
for subsequent processing steps, (iii) a combination of pins-up
followed by pins-down for subsequent processing steps, or (iv) a
combination of pins-down followed by pins-up followed by pins-down
for subsequent processing steps. Accordingly, a wide range of
flexibility is contemplated with respect to the use of the
lift-pins. The specific choice can be determined by the
requirements of the desired process results. Different options will
allow the process to be optimized to achieve different desired
process results. It should be appreciated that having the lift-pins
up (supporting the workpiece) can reduce the chance that the
workpiece may move (shift its location) on the workpiece support
structure during a rapid change in pressure. Of course, the
pins-up/pins-down combinations apply to both a single workpiece
located in a process chamber designed to process a single workpiece
or to a process chamber designed to process two or more work pieces
in parallel and/or serial combination.
[0073] Attention is now directed to FIG. 7 which illustrates a
system produced in accordance with the present invention and
generally indicated by the reference number 400. System 400 is
similar to previously described systems with the exception that it
employs dual workpiece processing stations. Accordingly, an "a" has
been appended to item reference numbers that are associated with a
first one of the processing stations while a "b" has been appended
to item reference numbers that are associated with a second one of
the processing stations. Processing stations a and b are located
within a shared processing chamber 32' such that both workpieces
are exposed to the same pressure environment. Accordingly, the
descriptions provided above, with respect to systems 10 and 80 are
considered to be equally applicable with respect to system 400
except that the workpieces can be processed in pairs so as to
enhance system throughput. Bypass valve arrangement 82 is also
illustrated, although there is no requirement to provide both the
backfill and bypass arrangements.
[0074] Having described the present invention in detail above, it
should be appreciated that, during processing of a series of
workpieces, it is never required, in the processing chamber, to
raise the process chamber pressure to more than the pressure used
for preheating. It is considered that such a requirement would
serve to reduce system throughput. Accordingly, the use of any
higher pressure (higher than the preheating pressure) in the
process chamber is completely avoided. Moreover, changing the
process chamber pressure between the preheating and treatment
pressures can always be accomplished very rapidly, irrespective of
whether the pressure change is increasing or decreasing. In
particular, the use of a backfilling approach from either a
backfill reservoir arrangement and/or using backfill from the
transfer chamber is highly advantageous in raising the process
chamber pressure from the treatment pressure to the preheating
pressure. Coupled with heating at the preheat pressure, an increase
in system throughput on the order of 20-50% is contemplated,
depending upon treatment time. Further, backfill from a backfill
reservoir and from the transfer chamber may be used in any desired
combination, either with serial or parallel use of the respective
backfill sources.
[0075] While the aforementioned '932 patent describes an AVA system
which is intended to minimize up-front costs, it is considered that
the present application provides many advantages over the use of an
AVA system. For example, system throughput is enhanced by
eliminating the need to return to atmospheric pressure, or some
higher load/unload pressure, subsequent to each workpiece being
processed. The present application transfers workpieces to and from
the process chamber at pressures that are at or below the workpiece
preheating pressure, thereby eliminating a number of pressure
changes that are mandated by the approach of the '932 patent.
Further, the present application provides for cooling
customization, described above, as the workpiece is returned to the
transfer chamber.
[0076] It is submitted that the prior art is devoid of the
recognition that is brought to light herein, whereby processing
chamber pressure rises can always be performed in a very rapid
manner when transitioning from the treatment pressure to the
preheating pressure. Moreover, the present application provides an
elegant and streamlined approach with respect to implementing
pressure changes in an overall process scheme, including the use of
backfilling in a way that is submitted to be missing from the prior
art.
[0077] It is to be understood that at least the following language
is considered to be enabled by the foregoing description.
[0078] 1. In a system for treating at least one workpiece using a
treatment process, said system having at least a transfer chamber
and a processing chamber such that a transfer chamber pressure, in
the transfer chamber, and a processing chamber pressure, in the
processing chamber, can each vary and the workpiece can be moved
between the transfer chamber and the processing chamber, said
system further including a process gas regulation arrangement for
providing process gas to said processing chamber at least during a
plasma treatment process at a given flow rate and which is capable
of providing said process gas at a maximum flow rate, a method
comprising:
[0079] a) equalizing the transfer chamber pressure and the
processing chamber pressure to a treatment pressure at which the
workpiece is to be subjected to a plasma treatment process;
[0080] b) transferring the workpiece from the transfer chamber to
the processing chamber at the treatment pressure;
[0081] c) preheating the workpiece to a treatment temperature, in
cooperation with raising the processing chamber pressure to a
preheating pressure at a pressure rise rate resulting at least in
part from using an additional process chamber gas input flow at an
input flow rate which causes an overall input rate to the
processing chamber to be greater than said maximum flow rate,
without raising the transfer chamber pressure;
[0082] d) reducing the processing chamber pressure to the treatment
pressure; and
[0083] e) exposing the workpiece to said plasma treatment process
at least approximately at said treatment pressure and at said
treatment temperature.
[0084] 2. The method of claim 1 wherein said pressure rise rate is
at least 15 Torr per second.
[0085] 3. The method of claim 1 wherein said workpiece supports a
photoresist layer and wherein said preheating and exposing
cooperate in removing the photoresist layer using said plasma
treatment process.
[0086] 4. The method of claim 3 wherein said plasma treatment
process produces a plasma which is customized for removing said
photoresist layer from the substrate at said treatment
temperature.
[0087] 5. The method of claim 1 wherein said workpiece is supported
by a susceptor and including heating the susceptor for use in
preheating the workpiece.
[0088] 6. The method of claim 5 wherein heating includes heating
the susceptor to an at least approximately fixed temperature.
[0089] 7. The method of claim 1 wherein said treatment pressure is
in a range from approximately 0.01 to 10 Torr.
[0090] 8. The method of claim 1 wherein said treatment pressure is
approximately 1 Torr.
[0091] 9. The method of claim 1 wherein said preheating pressure is
in a range from approximately 25 to 250 Torr.
[0092] 10. The method of claim 1 wherein said preheating pressure
is at least approximately 60 Torr.
[0093] 11. The method of claim 1 wherein preheating includes
introducing a preheating gas mixture into the processing chamber
for enhancing a rate of temperature increase of the workpiece.
[0094] 12. The method of claim 11 including using helium gas as at
least a portion of the preheating gas mixture.
[0095] 13. The method of claim 1 including configuring a backfill
reservoir arrangement for selective pressure communication with
said processing chamber for use in selectively producing a pressure
increase in said processing chamber by causing said additional
process chamber input flow, and preheating the workpiece in
cooperation with raising the processing chamber pressure includes
backfilling the processing chamber to said preheating pressure
using the additional process chamber gas input flow from the
backfill reservoir arrangement.
[0096] 14. The method of claim 13 wherein backfilling includes
using a gas diffuser for introducing the additional process chamber
gas input flow into the processing chamber from said backfill
reservoir arrangement.
[0097] 15. The method of claim 14 including generating a plasma, as
part of said plasma treatment process, using the process gas, and
the gas diffuser is further used for introducing the process gas
into the processing chamber.
[0098] 16. The method of claim 13 wherein said backfill reservoir
arrangement is configured to include a backfill reservoir and
storing a backfill gas in the backfill reservoir at a pressure that
is greater than a target pressure to which the processing chamber
is to be backfilled.
[0099] 17. The method of claim 16 wherein the target pressure is
selected as the preheating pressure for use during heating the
workpiece and heating the workpiece to a treatment temperature for
subsequent use during treating the workpiece.
[0100] 18. The method of claim 13 including causing a backfill
pressure in the backfill reservoir to rise to a selected value,
with the processing chamber at a treatment pressure that is lower
than the selected value and which treatment pressure is also lower
than a preheating pressure at which the workpiece is to be heated
to a treatment temperature and, thereafter, backfilling includes
placing the backfill reservoir in pressure communication with the
processing chamber in a way which causes the backfill pressure and
the treatment chamber pressure to equalize at least approximately
to the preheating pressure for subsequent use in enhancing a
heating rate of the workpiece.
[0101] 19. The method of claim 18 wherein said process gas
regulation arrangement provides at least approximately no process
gas during said backfilling.
[0102] 20. The method of claim 13 wherein said pressure rise rate
in the processing chamber is in a range of approximately 15 to 150
Torr per second.
[0103] 21. The method of claim 13 wherein backfilling includes
inducing said pressure rise rate in the processing chamber at
approximately 30 Torr per second.
[0104] 22. The method of claim 1 including simultaneously treating
a pair of workpieces according to steps (a) through (e).
[0105] 23. The method of claim 1 including processing a series of
workpieces according to steps (a) through (e).
[0106] 24. In a system for treating at least one workpiece, said
system having at least a transfer chamber and a processing chamber
such that a transfer chamber pressure, in the transfer chamber, and
a processing chamber pressure, in the processing chamber, can each
vary and the workpiece can be moved between the transfer chamber
and the processing chamber, said system further including a process
gas regulation arrangement for providing process gas to said
processing chamber at least during a plasma treatment process at a
given flow rate and which is capable of providing said process gas
at a maximum flow rate, an apparatus comprising:
[0107] a first arrangement at least for controlling the processing
chamber pressure to reduce the processing chamber pressure to a
treatment pressure at which the workpiece is to be subjected to a
plasma treatment process and for selectively raising the processing
chamber pressure, in cooperation with said process gas regulation
arrangement, to a preheating pressure, which is higher than the
treatment pressure, at a pressure rise rate resulting at least in
part from using an additional process chamber gas input flow at an
input flow rate which causes an overall input rate to the
processing chamber to be greater than said maximum flow rate,
without raising the transfer chamber pressure; and
[0108] a second arrangement in said processing chamber for
preheating the workpiece to a treatment temperature in cooperation
with raising the processing chamber pressure from said treatment
pressure to said preheating pressure, using said first arrangement,
and with said transfer chamber pressure remaining, at least
approximately, at said treatment pressure such that the processing
chamber pressure can then be reduced to the treatment pressure and
the workpiece exposed to said plasma treatment process at least
approximately at said treatment pressure and at said treatment
temperature.
[0109] 25. The apparatus of claim 24 wherein said pressure rise
rate is at least 15 Torr per second.
[0110] 26. The apparatus of claim 24 wherein said treatment
pressure is in a range from approximately 0.01 to 10 Torr.
[0111] 27. The apparatus of claim 24 wherein said treatment
pressure is approximately 1 Torr.
[0112] 28. The apparatus of claim 24 wherein said preheating
pressure is in range from approximately 25 to 250 Torr.
[0113] 29. The apparatus of claim 24 configured for treating a pair
of workpieces simultaneously.
[0114] 30. The apparatus of claim 24 including processing a series
of workpieces according to steps (a) through (e).
[0115] 31. The apparatus of claim 24 wherein said first arrangement
includes a backfill reservoir arrangement for selective pressure
communication with said processing chamber for use in selectively
backfilling, as said additional process chamber gas input flow, the
processing chamber pressure from the treatment pressure to the
preheating pressure.
[0116] 32. The apparatus of claim 31 wherein the backfill
arrangement includes a gas diffuser for introducing the additional
process chamber gas input flow into the processing chamber.
[0117] 33. The apparatus of claim 32 wherein said processing
chamber includes a plasma generator for generating a plasma, as
part of said plasma treatment process, using the process gas and
the gas diffuser is configured for introducing the process gas into
the processing chamber.
[0118] 34. The apparatus of claim 31 wherein said backfill
reservoir arrangement includes a backfill reservoir for storing a
backfill gas at a backfill pressure that is greater than the
preheating pressure to which the processing chamber is to be
backfilled.
[0119] 35. The apparatus of claim 34 including a control
arrangement for causing the backfill pressure in the backfill
reservoir to rise to a selected value, with the processing chamber
at a treatment pressure that is lower than the selected value and
which treatment pressure is also lower than a preheating pressure
at which the workpiece is to be heated to a treatment temperature
and, thereafter, to backfill the processing chamber by placing the
backfill reservoir in pressure communication with the processing
chamber in a way which causes the backfill pressure and the
treatment chamber pressure to equalize at least approximately to
the preheating pressure for subsequent use in enhancing a heating
rate of the workpiece.
[0120] 36. The apparatus of claim 35 wherein said process gas
regulation arrangement provides at least approximately no process
gas during said backfilling.
[0121] 37. In a system for treating at least one workpiece, said
system having at least a transfer chamber and a processing chamber
such that a transfer chamber pressure, in the transfer chamber, and
a processing chamber pressure, in the processing chamber, can each
be controlled and the workpiece can be moved between the transfer
chamber and the processing chamber, said system further including a
process gas regulation arrangement for providing process gas to
said processing chamber at least during a plasma treatment process
at a given flow rate and which is otherwise capable of providing
said process gas at a maximum flow rate, a method comprising:
[0122] manipulating at least the processing chamber pressure and
cooperatively moving the workpiece between the transfer chamber and
the processing chamber such that the workpiece is exposed to a
preheating pressure in the processing chamber for use in heating
the workpiece to a treatment temperature and so that the workpiece
is subjected to a treatment process in the processing chamber, at
least approximately at a treatment pressure that is lower than the
preheating pressure, after having at least approximately reached
the treatment temperature, in a way which produces a maximum
processing chamber pressure of no more than approximately the
preheating pressure using a value of the preheating pressure that
is less than atmospheric pressure, and using a rate of pressure
increase in the processing chamber from the treatment pressure to
the preheating pressure resulting at least in part from using an
additional process chamber gas input flow at an input flow rate
which causes an overall input rate to the processing chamber to be
greater than said maximum flow rate, without raising the transfer
chamber pressure.
[0123] 38. The method of claim 37 wherein said rate of pressure
increase is at least 15 Torr per second.
[0124] 39. The method of claim 37 wherein manipulating includes
maintaining the transfer chamber pressure at least approximately at
the treatment pressure.
[0125] 40. The method of claim 37 wherein manipulating includes
maintaining the transfer chamber pressure at least approximately at
the preheating pressure.
[0126] 41. In a system for treating at least one workpiece in
accordance with a multi-step overall process which preheats said
workpiece in a processing chamber to a treatment temperature at a
preheating pressure and, thereafter, exposes said workpiece to a
plasma at a treatment pressure in the processing chamber and at
least approximately at said treatment temperature, said treatment
pressure being less than said preheating pressure such that the
processing chamber pressure must be raised from the treatment
pressure at least to the preheating pressure at one or more points
during the multi-step overall process, said system further
including a process gas regulation arrangement for providing
process gas to said processing chamber at least during exposing the
workpiece to said plasma at a given flow rate and which is capable
of providing said process gas at a maximum flow rate, a
configuration forming part of said system, said configuration
comprising:
[0127] an arrangement for use in raising the processing chamber
pressure from the treatment pressure at least to the preheating
pressure at said one or more points during the multi-step overall
process by providing an additional process chamber gas input flow
at an input flow rate which causes an overall input rate to the
processing chamber to be greater than said maximum flow rate.
[0128] 42. In a system for treating at least one workpiece, said
system having at least a transfer chamber and a processing chamber
such that a transfer chamber pressure, in the transfer chamber, and
a processing chamber pressure, in the processing chamber, can each
vary and the workpiece can be moved between the transfer chamber
and the processing chamber, and said workpiece is heated to a
treatment temperature at a preheating pressure and exposed to a
treatment process at a treatment pressure that is less than the
preheating pressure, an apparatus comprising:
[0129] a backfill reservoir arrangement for selective pressure
communication with said processing chamber for use in selectively
backfilling the processing chamber pressure from the treatment
pressure at least to the preheating pressure.
[0130] 43. The apparatus of claim 42 wherein the backfill
arrangement includes a gas diffuser for introducing a backfill gas
into the processing chamber.
[0131] 44. The apparatus of claim 43 wherein said processing
chamber includes a plasma generator for generating a plasma, as
part of said treatment process, using a plasma gas and the gas
diffuser is configured for introducing the plasma gas into the
processing chamber.
[0132] 45. The apparatus of claim 42 wherein said backfill
reservoir arrangement includes a backfill reservoir for storing a
backfill gas at a backfill pressure that is greater than the
preheating pressure to which the processing chamber is to be
backfilled.
[0133] 46. The apparatus of claim 45 including a control
arrangement for causing the backfill pressure in the backfill
reservoir to rise to a selected value, with the processing chamber
at the treatment pressure that is lower than the selected value
and, thereafter, to backfill the processing chamber by placing the
backfill reservoir in pressure communication with the processing
chamber in a way which causes the backfill pressure and the
treatment chamber pressure to equalize at least approximately to
the preheating pressure for subsequent use in enhancing a heating
rate of the workpiece.
[0134] 47. In a system for treating at least one workpiece, said
system having at least a transfer chamber and a processing chamber
such that a transfer chamber pressure, in the transfer chamber, and
a processing chamber pressure, in the processing chamber, can each
vary and the workpiece can be moved between the transfer chamber
and the processing chamber, said system further including a process
gas regulation arrangement for providing process gas to said
processing chamber at least during a plasma treatment process at a
given flow rate and which is capable of providing said process gas
at a maximum flow rate, a method comprising:
[0135] a) equalizing the transfer chamber pressure and the
processing chamber pressure to a preheating pressure at which the
workpiece is to be heated to a treatment temperature;
[0136] b) in cooperation with equalizing the transfer chamber
pressure and the processing chamber pressure, transferring the
workpiece from the transfer chamber to the processing chamber;
[0137] c) preheating the workpiece to a treatment temperature at
the preheating pressure in the processing chamber;
[0138] d) reducing the processing chamber pressure to the treatment
pressure while the transfer chamber remains at least approximately
at the preheating pressure;
[0139] e) exposing the workpiece to a plasma treatment process at
least approximately at said treatment pressure and at said
treatment temperature;
[0140] f) raising the processing chamber pressure at least to the
preheating pressure at a pressure rise rate resulting at least in
part from using an additional process chamber gas input flow at an
input flow rate which causes an overall input rate to the
processing chamber to be greater than said maximum flow rate;
and
[0141] g) in cooperation with raising the processing chamber
pressure, moving the workpiece from the processing chamber to the
transfer chamber.
[0142] 48. The method of claim 47 wherein said pressure rise rate
is at least 15 Torr per second.
[0143] 49. The method of claim 47 including configuring a backfill
reservoir arrangement for selective pressure communication with
said processing chamber for use in selectively producing a pressure
increase in said processing chamber, and raising the processing
chamber pressure to the treatment pressure at said pressure rise
rate includes backfilling the processing chamber to said preheating
pressure using the backfill reservoir arrangement.
[0144] 50. The method of claim 49 wherein said backfill reservoir
arrangement is configured to include a backfill reservoir and
including storing a backfill gas in the backfill reservoir at a
pressure that is greater than a target pressure to which the
processing chamber is to be backfilled.
[0145] 51. The method of claim 50 wherein backfilling causes a
backfill pressure in the backfill reservoir to rise to a selected
value, with the processing chamber at the treatment pressure, which
treatment pressure is lower than the selected value and which is
also lower than the preheating pressure at which the workpiece is
to be heated to the treatment temperature and, thereafter, placing
the backfill reservoir in pressure communication with the
processing chamber in a way which causes the backfill pressure and
the treatment chamber pressure to equalize at least approximately
to the preheating pressure for subsequent use in enhancing a
heating rate of the workpiece.
[0146] 52. The method of claim 49 wherein backfilling includes
inducing a rate of pressure rise in a range from approximately 10
to 150 Torr per second in the processing chamber.
[0147] 53. The method of claim 47 wherein said workpiece supports a
photoresist layer and wherein said preheating and exposing steps
are configured to cooperate in removing the photoresist layer using
said plasma treatment process.
[0148] 54. The method of claim 53 wherein said plasma treatment
process produces a plasma which is customized for removing said
photoresist layer from the substrate at said treatment
temperature.
[0149] 55. The method of claim 47 wherein said workpiece is
supported by a susceptor and including heating the susceptor for
use in preheating the workpiece.
[0150] 56. The method of claim 55 wherein heating includes heating
the susceptor to an at least approximately fixed temperature.
[0151] 57. The method of claim 47 wherein said preheating pressure
is in a range from approximately 25 to 250 Torr.
[0152] 58. The method of claim 47 wherein said preheating pressure
is at least approximately 60 Torr.
[0153] 59. The method of claim 47 wherein preheating includes
introducing a preheating gas mixture into the processing chamber
for enhancing a rate of temperature increase of the workpiece.
[0154] 60. The method of claim 59 including using helium gas as at
least a portion of the preheating gas mixture.
[0155] 61. The method of claim 47 including simultaneously treating
a pair of workpieces according to steps (a) through (g).
[0156] 62. The method of claim 47 including processing a series of
workpieces according to steps (a) through (g).
[0157] 63. In a system for treating at least one workpiece, said
system having at least a transfer chamber and a processing chamber
such that a transfer chamber pressure, in the transfer chamber, and
a processing chamber pressure, in the processing chamber, can each
vary and the workpiece can be moved between the transfer chamber
and the processing chamber, a method comprising:
[0158] a) in pressure isolation from the process chamber, changing
the transfer chamber pressure to a selected pressure value that is
greater than a preheating pressure at which the workpiece is to be
heated at least approximately to a treatment temperature;
[0159] b) with the processing chamber initially at least
approximately at a treatment pressure, which is lower than the
preheating pressure, equalizing pressure between the transfer
chamber and the processing chamber such that the selected pressure
backfills the process chamber at least approximately to the
preheating pressure;
[0160] c) in cooperation with equalizing pressure to the preheating
pressure, moving the workpiece from the transfer chamber to the
processing chamber;
[0161] d) preheating the workpiece, at least approximately, to a
treatment temperature at the preheating pressure in the processing
chamber;
[0162] e) reducing the processing chamber pressure to the treatment
pressure, in pressure isolation from the transfer chamber pressure;
and
[0163] f) exposing the workpiece to a plasma treatment process at
least approximately at said treatment pressure and at least
approximately at said treatment temperature.
[0164] 64. The method of claim 63 further comprising:
[0165] g) after equalizing pressure between the transfer chamber
and processing chamber and in pressure isolation from the
processing chamber, raising the transfer chamber pressure from the
preheating pressure to the selected pressure value;
[0166] h) with the processing chamber at least approximately at the
treatment pressure after exposing the workpiece to the plasma
treatment process and with the transfer chamber at the selected
pressure value, re-equalizing pressure between the transfer chamber
and the processing chamber such that the selected pressure value
causes the processing chamber to backfill at least approximately to
the preheating pressure;
[0167] i) transferring the workpiece from the treatment chamber to
the transfer chamber in cooperation with re-equalizing the transfer
chamber pressure and the treatment chamber pressure.
[0168] 65. The method of claim 64 further comprising:
[0169] j) after re-equalizing, repeating steps (c) through (i) for
at least one additional workpiece.
[0170] 66. The method of claim 63 wherein an isolation valve
selectively provides pressure communication between the transfer
chamber and the processing chamber and wherein said equalizing
includes opening the isolation valve and said workpiece is movable
through the isolation valve.
[0171] 67. The method of claim 63 wherein a bypass arrangement
selectively provides pressure communication between the transfer
chamber and the processing chamber for use in said equalizing and
an isolation valve between the transfer chamber and the processing
chamber provides at least for movement of the workpiece
therethrough between the transfer chamber and the processing
chamber.
[0172] 68. The method of claim 63 including choosing the selected
pressure based, at least in part, on a processing chamber volume of
the processing chamber and a transfer chamber volume of the
transfer chamber.
[0173] 69. In a system for treating at least one workpiece, said
system having at least a transfer chamber and a processing chamber
such that a transfer chamber pressure, in the transfer chamber, and
a processing chamber pressure, in the processing chamber, can each
vary and the workpiece can be moved between the transfer chamber
and the processing chamber, an apparatus, comprising:
[0174] a first arrangement for changing the transfer chamber
pressure, in pressure isolation from the process chamber, to a
selected pressure value that is greater than a preheating pressure
at which the workpiece is to be heated at least approximately to a
treatment temperature; and
[0175] a second arrangement for equalizing pressure between the
transfer chamber and the processing chamber with the processing
chamber initially at least approximately at a treatment pressure,
which is lower than the preheating pressure, such that the selected
pressure backfills the process chamber at least approximately to
the preheating pressure.
[0176] 70. The apparatus of claim 69 including an isolation valve
through which said workpiece is moved between the transfer chamber
and the process chamber and which is configured to selectively
provide pressure communication between the transfer chamber and the
processing chamber for pressure equalization.
[0177] 71. The apparatus of claim 69 wherein a bypass arrangement
selectively provides pressure communication between the transfer
chamber and the processing chamber for use in said equalizing and
an isolation valve between the transfer chamber and the processing
chamber provides at least for movement of the workpiece
therethrough between the transfer chamber and the processing
chamber.
[0178] 72. In a system for treating at least one workpiece, said
system having at least a transfer chamber and a processing chamber
such that a transfer chamber pressure, in the transfer chamber, and
a processing chamber pressure, in the processing chamber, can each
be controlled and the workpiece can be moved between the transfer
chamber and the processing chamber, a method comprising:
[0179] manipulating at least the processing chamber pressure and
cooperatively moving the workpiece between the transfer chamber and
the processing chamber such that the workpiece is exposed to a
preheating pressure in the processing chamber for use in heating
the workpiece to a treatment temperature and so that the workpiece
is subjected to a treatment process in the processing chamber, at
least approximately at a treatment pressure that is lower than the
preheating pressure, after having at least approximately reached
the treatment temperature, in a way which produces a maximum
processing chamber pressure of no more than approximately the
preheating pressure using a value of the preheating pressure that
is less than atmospheric pressure, but greater than the treatment
pressure and manipulating includes raising the transfer chamber
pressure to a selected value and, thereafter, causing pressure
communication between the transfer chamber and the processing
chamber which results in the transfer chamber pressure decreasing
in a range from the selected value to the preheating pressure in a
way which backfills the processing chamber so as to increase the
processing chamber pressure from the treatment pressure to the
preheating pressure.
[0180] 73. The method of claim 72 including initiating movement of
the workpiece between the transfer chamber and the processing
chamber in timed relation to the transfer chamber pressure decrease
in said range between the selected value and the preheating
pressure.
[0181] 74. The method of claim 72 wherein a bypass arrangement
selectively provides pressure communication between the transfer
chamber and the processing chamber for use in said equalizing and
an isolation valve between the transfer chamber and the processing
chamber provides at least for movement of the workpiece
therethrough between the transfer chamber and the processing
chamber.
[0182] 75. In treating a plurality of workpieces using a system
having at least a transfer chamber and a processing chamber such
that a transfer chamber pressure, in the transfer chamber, and a
processing chamber pressure, in the processing chamber, can each
vary and each workpiece of the plurality of workpieces can be moved
between the transfer chamber and the processing chamber, said
system further including a process gas regulation arrangement for
providing process gas to said processing chamber at least during a
plasma treatment process at a given flow rate and which is
otherwise capable of providing said process gas at a maximum flow
rate, a method comprising:
[0183] manipulating at least the processing chamber pressure and
cooperatively moving a first one of the workpieces between the
transfer chamber and the processing chamber such that the first
workpiece is exposed to a preheating pressure in the processing
chamber for use in heating the first workpiece to a treatment
temperature and so that the first workpiece is subjected to a
treatment process in the processing chamber, at least approximately
at a treatment pressure, that is lower than the preheating
pressure, after having at least approximately reached the treatment
temperature, in a way which produces a maximum processing chamber
pressure of no more than approximately the preheating pressure,
using a value of the preheating pressure that is less than
atmospheric pressure, and using a rate of pressure increase in the
processing chamber from the treatment pressure to the preheating
pressure resulting at least in part from using an additional
process chamber gas input flow at an input flow rate which causes
an overall input rate to the processing chamber to be greater than
said maximum flow rate, without raising the transfer chamber
pressure.
[0184] 76. The method of claim 75 further comprising:
[0185] treating subsequent ones of the plurality of workpieces by
continuing to manipulate the transfer chamber pressure, the
processing chamber pressure and cooperatively moving each one of
the subsequent ones of the workpieces between the transfer chamber
and the processing chamber such that the subsequent ones of the
workpieces are exposed to the preheating pressure in the processing
chamber for use in heating each of the subsequent ones of the
workpieces to the treatment temperature and so that the subsequent
ones of the workpieces are subjected to the treatment process in
the processing chamber, at least approximately at the treatment
pressure, after having at least approximately reached the treatment
temperature in said way which produces the maximum processing
chamber pressure of no more than approximately the preheating
pressure, using a value of the preheating pressure that is less
than atmospheric pressure.
[0186] 77. The method of claim 75 wherein manipulating includes
maintaining the transfer chamber pressure at least approximately at
the treatment pressure while treating said plurality of
workpieces.
[0187] 78. The method of claim 75 wherein manipulating includes
maintaining the transfer chamber pressure at least approximately at
the preheating pressure while treating said plurality of
workpieces.
[0188] 79. The method of claim 75 including simultaneously
subjecting a multiple number of said workpieces to the treatment
process.
[0189] 80. In treating a plurality of workpieces using a system
having at least a transfer chamber and a processing chamber such
that a transfer chamber pressure, in the transfer chamber, and a
processing chamber pressure, in the processing chamber, can each
vary and each workpiece of the plurality of workpieces can be moved
between the transfer chamber and the processing chamber, a method
comprising:
[0190] manipulating the transfer chamber pressure and the
processing chamber pressure and cooperatively moving each of the
workpieces between the transfer chamber and the processing chamber
such that the each workpiece is exposed to a preheating pressure in
the processing chamber for use in heating each workpiece to a
treatment temperature and so that each workpiece is subjected to a
treatment process in the processing chamber, at least approximately
at a treatment pressure, that is lower than the preheating
pressure, after having at least approximately reached the treatment
temperature, in a way which produces a maximum processing chamber
pressure of no more than approximately the preheating pressure,
using a value of the preheating pressure that is less than
atmospheric pressure, and manipulating includes pressure cycling
the transfer chamber between a selected pressure and the preheating
pressure in timed relation to treating each workpiece, said
pressure cycling at least in part resulting from establishing
pressure communication between the transfer chamber and the
processing chamber such that the selected pressure is used to
backfill the processing chamber.
[0191] 81. The method of claim 80 including initiating movement of
the workpiece between the transfer chamber and the processing
chamber in timed relation to the transfer chamber pressure decrease
in said range from the selected value to the preheating
pressure.
[0192] 82. In a system for treating at least one workpiece, said
system having at least a transfer chamber and a processing chamber
such that a transfer chamber pressure, in the transfer chamber, and
a processing chamber pressure, in the processing chamber, can each
vary and the workpiece can be moved between the transfer chamber
and the processing chamber through an isolation valve, a
configuration, comprising:
[0193] a bypass arrangement for selectively providing pressure
communication between the transfer chamber and the processing
chamber for use in pressure equalization therebetween without a
need to use said isolation valve.
[0194] 83. The configuration of claim 82 wherein said bypass
arrangement includes a bypass valve for selectively controlling the
pressure communication between the transfer chamber and the
processing chamber.
[0195] 84. The configuration of claim 83 wherein said bypass
arrangement is configured to induce a pressure increase in said
processing chamber at a rate of at least 15 Torr per second.
[0196] 85. The configuration of claim 83 wherein said bypass
arrangement is configured to induce a pressure increase in the
processing chamber from said treatment pressure to said preheating
pressure characterized by a rate of pressure increase of greater
than 30 Torr per second.
[0197] 86. The configuration of claim 82 including a control
arrangement for causing the transfer chamber pressure to rise to a
selected value, with the processing chamber at a treatment
pressure, that is lower than the selected value and which is also
lower than a preheating pressure at which the workpiece is to be
heated to a treatment temperature and, thereafter, to backfill the
processing chamber by opening at least the bypass arrangement
between the transfer chamber and the processing chamber in a way
which causes the processing chamber pressure and the treatment
chamber pressure to equalize at least approximately to the
preheating pressure for subsequent use in heating the
workpiece.
[0198] 87. In a system for treating at least one workpiece, said
system having at least a transfer chamber and a processing chamber
such that a transfer chamber pressure, in the transfer chamber, and
a processing chamber pressure, in the processing chamber, can each
vary and the workpiece can be moved between the transfer chamber
and the processing chamber through an isolation valve, a
configuration, comprising:
[0199] said isolation valve configured for selectively providing
pressure communication between the transfer chamber and the
processing chamber for use in pressure equalization therebetween to
induce a rate of pressure increase in the processing chamber of at
least 15 Torr per second.
[0200] 88. The configuration of claim 87 including a control
arrangement for causing the transfer chamber pressure to rise to a
selected value, with the processing chamber at a treatment
pressure, that is lower than the selected value and which is also
lower than a preheating pressure at which the workpiece is to be
heated to a treatment temperature and, thereafter, to backfill the
processing chamber by opening the isolation valve in a way which
causes the processing chamber pressure and the treatment chamber
pressure to equalize at least approximately to the preheating
pressure for subsequent use in heating the workpiece.
[0201] 89. In a system for treating at least one workpiece, said
system having at least a transfer chamber and a processing chamber
such that a transfer chamber pressure, in the transfer chamber, and
a processing chamber pressure, in the processing chamber, can each
vary and the workpiece can be moved between the transfer chamber
and the processing chamber through an isolation valve, a
configuration, comprising:
[0202] a backfill arrangement in selective pressure communication
with said processing chamber for use in inducing a pressure
increase in said processing chamber.
[0203] 90. The configuration of claim 89 wherein said processing
chamber includes a gas diffuser that is configured for introducing
a backfill gas from said backfill arrangement.
[0204] 91. The configuration of claim 89 wherein said backfill
arrangement includes a backfill reservoir for storing a backfill
gas at a pressure that is greater than a target pressure to which
the processing chamber is to be backfilled.
[0205] 92. The configuration of claim 91 wherein the target
pressure is a preheating pressure at which said workpiece is
heated, at least approximately, to a treatment temperature for
subsequent use in treating the workpiece.
[0206] 93. The configuration of claim 91 wherein the backfill
arrangement includes a backfill valve for controlling pressure
communication between the transfer chamber and the processing
chamber.
[0207] 94. The configuration of claim 91 including a control
arrangement for causing a backfill pressure in the backfill
reservoir rise to a selected value, with the processing chamber at
a treatment pressure, that is lower than the selected value and
which is also lower than a preheating pressure at which the
workpiece is to be heated to a treatment temperature and,
thereafter, to backfill the processing chamber by placing the
backfill reservoir in pressure communication with the processing
chamber in a way which causes the backfill pressure and the
treatment chamber pressure to equalize at least approximately to
the preheating pressure for subsequent use in enhancing a heating
rate of the workpiece.
[0208] 95. The configuration of claim 89 wherein said backfill
arrangement is configured for inducing a pressure rise in the
processing chamber at a rate of at least 15 Torr per second.
[0209] 96. The configuration of claim 90 wherein said system is
configured for exposing said workpiece to a plasma at a treatment
temperature and for heating the workpiece to a treatment
temperature prior to exposing the workpiece to the plasma in the
processing chamber and said plasma is generated using a plasma gas
in a plasma chamber forming part of the processing chamber and
wherein said processing chamber includes a gas diffuser that is
configured for introducing a backfill gas from said backfill
arrangement and which is further configured for introducing said
plasma gas.
[0210] Although each of the aforedescribed physical embodiments
have been illustrated with various components having particular
respective orientations, it should be understood that the present
invention may take on a variety of specific configurations with the
various components being located in a wide variety of positions and
mutual orientations. Furthermore, the methods described herein may
be modified in an unlimited number of ways, for example, by
reordering, modifying and recombining the various steps. For
example, any action taken responsive to or in timed relation to a
particular event may occur at any point within an interval centered
on that particular event, which interval may be defined in terms of
any of time, pressure or temperature. As another example, with the
present disclosure in hand, it should be appreciated that two or
more transfer chambers can be operated when connected to a common
transfer chamber, consistent with the teachings herein.
Accordingly, it should be apparent that the arrangements and
associated methods disclosed herein may be provided in a variety of
different configurations and modified in an unlimited number of
different ways, and that the present invention may be embodied in
many other specific forms without departing from the spirit or
scope of the invention. Therefore, the present examples and methods
are to be considered as illustrative and not restrictive, and the
invention is not to be limited to the details given herein, but may
be modified at least within the scope of the appended claims.
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