U.S. patent application number 17/706090 was filed with the patent office on 2022-07-14 for processing of semiconductors using vaporized solvents.
The applicant listed for this patent is Beijing E-Town Semiconductor Technology, Co., LTD, Mattson Technology, Inc.. Invention is credited to Shawming Ma, Shuang Meng, Michael X. Yang.
Application Number | 20220223405 17/706090 |
Document ID | / |
Family ID | |
Filed Date | 2022-07-14 |
United States Patent
Application |
20220223405 |
Kind Code |
A1 |
Meng; Shuang ; et
al. |
July 14, 2022 |
Processing of Semiconductors Using Vaporized Solvents
Abstract
Processes and apparatuses for the treatment of semiconductor
workpieces are provided. In some embodiments, a method can include
placing the workpiece into a process chamber; vaporizing a solvent
to create a vaporized solvent; introducing the vaporized solvent
into the process chamber; and exposing the workpiece to the
vaporized solvent.
Inventors: |
Meng; Shuang; (Newark,
CA) ; Ma; Shawming; (Sunnyvale, CA) ; Yang;
Michael X.; (Palo Alto, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Beijing E-Town Semiconductor Technology, Co., LTD
Mattson Technology, Inc. |
Beijing
Fremont |
CA |
CN
US |
|
|
Appl. No.: |
17/706090 |
Filed: |
March 28, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16208003 |
Dec 3, 2018 |
11289323 |
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17706090 |
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62599105 |
Dec 15, 2017 |
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International
Class: |
H01L 21/02 20060101
H01L021/02; H01L 21/67 20060101 H01L021/67; H01J 37/32 20060101
H01J037/32 |
Claims
1-11. (canceled)
12. A semiconductor workpiece processing apparatus comprising: a
solvent storage receptacle; a vaporizer configured to vaporize a
solvent from the solvent storage receptacle to generate a vaporized
solvent; a process chamber; a plasma chamber having an RF source
operable to generate a plasma, the plasma chamber being remote from
the process chamber; and a solvent line that connects the solvent
storage receptacle to the process chamber, the solvent line
operable to introduce the vaporized solvent into the process
chamber.
13. The semiconductor workpiece processing apparatus of claim 11,
wherein the solvent comprises one or more of one or more of
isopropyl alcohol (IPA), acetone, methanol, N-methyl-2-pyrrolidone
(NMP), N-ethyl-2-pyrrolidone (NEP), dimethyl sulfoxide (DMSO),
propylene glycol methyl ether acetate (PGMEA), methyl ethyl ketone
(MEK), n-Butyl acetate (NBA), .gamma.-butyrolactone (GBL),
propylene carbonate (PC), triethylamine (TEA), and
acetonitrile.
14. The apparatus of claim 12, wherein the plasma chamber is
connected between the solvent line and the process chamber.
15. The apparatus of claim 14, further comprising a separation grid
separating the plasma chamber from the process chamber.
16. The apparatus of claim 12, further comprising a mass flow meter
or a volumetric flow meter on the solvent line.
17. The apparatus of claim 12, wherein the solvent storage
receptacle is a liquid tank, a compressed gas tank, or an
ampoule.
18. The apparatus of claim 12, wherein the solvent line feeds
directly into the process chamber and bypasses a plasma chamber and
a separation grid separating the plasma chamber from the process
chamber.
19. The apparatus of claim 12, wherein the solvent line feeds
directly into a separation grid separating the plasma chamber from
the process chamber.
20. The apparatus of claim 19, wherein the solvent line feeds
directly between a plurality of grid plates in the separation grid.
Description
PRIORITY CLAIM
[0001] The present application is based on and claims priority to
U.S. Provisional Application No. 62/599,105, having a filing date
of Dec. 15, 2017, which is incorporated by reference herein.
FIELD
[0002] The present disclosure relates generally to treatment of a
workpiece using vaporized solvents.
BACKGROUND
[0003] Post-implantation photoresist removal and post-etch residue
removal have been traditionally accomplished using an
oxygen-containing plasma dry strip. However, the resultant silicon
(Si) or silicon-germanium (SiGe) loss from the oxidizing chemistry
can cause degradation of device performance, and the interaction of
oxygen radicals with low-k films can cause low-k damage. Strip
processes based on reducing chemistries (e.g. hydrogen and
nitrogen) generally result in lower substrate loss. However, these
types of processes do not completely resolve the material loss
issue while also introducing additional problems. For example,
hydrogen-based processes have low resist removal rates and hydrogen
plasma can also cause device shifts due to vacancy formation deep
inside the Si and SiGe substrates. Therefore, there is a need for
new chemistries to be introduced into the dry strip process to meet
increasing product performance requirements.
SUMMARY
[0004] Aspects and advantages of embodiments of the present
disclosure will be set forth in part in the following description,
or may be learned from the description, or may be learned through
practice of the embodiments.
[0005] One example aspect of the present disclosure is directed to
a method for processing a workpiece. The method can include placing
the workpiece into a process chamber. The method can include
vaporizing a solvent to create a vaporized solvent. The method can
include introducing the vaporized solvent into the process chamber.
The method can include exposing the workpiece to the vaporized
solvent.
[0006] Other example aspects of the present disclosure are directed
to systems, methods, and apparatuses for processing of
workpieces.
[0007] These and other features, aspects and advantages of various
embodiments will become better understood with reference to the
following description and appended claims. The accompanying
drawings, which are incorporated in and constitute a part of this
specification, illustrate embodiments of the present disclosure
and, together with the description, serve to explain the related
principles.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Detailed discussion of embodiments directed to one of
ordinary skill in the art are set forth in the specification, which
makes reference to the appended figures, in which:
[0009] FIG. 1 depicts a semiconductor workpiece processing
apparatus according to example embodiments of the present
disclosure;
[0010] FIG. 2 depicts a flow diagram of a method according to
example embodiments of the present disclosure;
[0011] FIG. 3 depicts a flow diagram of a method according to
example embodiments of the present disclosure;
[0012] FIG. 4 depicts a semiconductor workpiece processing
apparatus according to example embodiments of the present
disclosure;
[0013] FIG. 5 depicts a semiconductor workpiece processing
apparatus according to example embodiments of the present
disclosure;
[0014] FIG. 6 depicts a semiconductor workpiece processing
apparatus according to example embodiments of the present
disclosure;
[0015] FIG. 7 depicts a semiconductor workpiece processing
apparatus according to example embodiments of the present
disclosure;
[0016] FIG. 8 depicts an example separation grid according to
example embodiments of the present disclosure; and
[0017] FIG. 9 depicts a semiconductor workpiece processing
apparatus according to example embodiments of the present
disclosure.
DETAILED DESCRIPTION
[0018] Reference now will be made in detail to embodiments, one or
more examples of which are illustrated in the drawings. Each
example is provided by way of explanation of the embodiments, not
limitation of the present disclosure. In fact, it will be apparent
to those skilled in the art that various modifications and
variations can be made to the embodiments without departing from
the scope or spirit of the present disclosure. For instance,
features illustrated or described as part of one embodiment can be
used with another embodiment to yield a still further embodiment.
Thus, it is intended that aspects of the present disclosure cover
such modifications and variations.
[0019] Example aspects of the present disclosure are directed to
semiconductor workpiece processing. More specifically, in some
embodiments, example aspects of the present disclosure are directed
toward workpiece surface cleaning, such as post-implantation
photoresist and post-etch residue removal. The processes and
apparatuses discussed herein can be used in both front-end-of-line
and back-end-of-line applications.
[0020] Embodiments can include a non-oxidizing dry-strip process
that uses injecting of solvent chemicals into a process chamber to
facilitate photoresist and post-etch residue removal. Embodiments
can perform effective photoresist strip and residue removal with
reduced surface damage and oxidation. The workpieces (e.g., Si and
SiGe wafers) can be exposed to the chemical vapor of the solvent.
The vaporized solvent can attack photoresist and post-etch residues
on the workpiece surface. Furthermore, in some embodiments, a
plasma can be generated and applied in combination with solvent
vapor. The workpiece can then be exposed to radicals generated in
the plasma which can assist in workpiece cleaning.
[0021] Example aspects of the present disclosure are discussed with
reference to treating a semiconductor wafer workpiece for purposes
of illustration and discussion. Those of ordinary skill in the art,
using the disclosures provided herein, will understand that aspects
of the present disclosure can be used in conjunction with the
processing of other workpieces without deviating from the scope of
the present disclosure. As used herein, the use of the term "about"
in conjunction with a numerical value can refer to within 20% of
the stated numerical value.
[0022] FIG. 1 depicts a semiconductor workpiece processing
apparatus 100 according to example embodiments of the present
disclosure. A solvent storage receptacle 103 containing a solvent
is positioned upstream of the process chamber 110 and has a solvent
feed gas line 101.
[0023] The solvent storage receptacle 103 can be in the form of a
liquid tank. The solvent feed gas line 101 can introduce a carrier
gas to the solvent storage receptacle 103. The carrier gas can be
inert (e.g., noble gas, nitrogen, etc.) or can otherwise be
chemically active in the process.
[0024] The solvent feed gas line 101 can supply pressure to the
solvent storage receptacle 103 to drive the solvent forward in the
process through the solvent storage receptacle outlet line 119.
Alternatively (or in conjunction), a solvent pump 121 can be
provided on the solvent storage receptacle outlet line 119 to pull
solvent from the solvent storage receptacle 103 and push the
solvent through the solvent line 120 to the vaporizer 105. The
solvent pump 121 (e.g., a positive displacement pump) can also
serve to control the mass flow rate of solvent being sent to the
vaporizer 105. A mass flow meter (MFM) 106 and/or a volumetric flow
meter (not shown) can be provided on the solvent line 120. The mass
flow meter 106 and/or volumetric flow meter can be located before
or after the vaporizer 105 and can send information to a controller
(not shown) to control the amount of solvent sent to the process
chamber 110.
[0025] The controller can be any suitable control device for
controlling operation of the system. For instance, the controller
can include one or more processors and one or more memory devices.
The one or more memory devices can store computer-readable
instructions that when executed by the one or more processors cause
the one or more processors to perform operations. The operations
can include controlling flow of the solvent based on signals from
the mass flow meter and/or volumetric flow meter. The vaporizer 105
can serve to vaporize liquid solvent coming from the solvent
storage receptacle 103 and deliver the vaporized solvent downstream
to the plasma chamber 111 and/or the process chamber 110 via the
solvent line 120.
[0026] A purge gas line 102 can be connected to the solvent line
120 to, for example, purge out residue liquids in the solvent line
120 during system maintenance. A drain line 140 can be connected to
the solvent line 120 for cleaning and maintenance of the processing
apparatus 100. Furthermore, a bypass line 107 can be connected to
the solvent line 120 such that the solvent bypasses the plasma
chamber 111 and process chamber 110. The bypass line 107 can be
particularly useful for obtaining the correct flow rate and
composition in the solvent line 120 prior to administering the
contents of the solvent line 120 to the plasma chamber 111 and the
process chamber 110. The bypass line 107 can feed directly into the
process chamber evacuation pump 118 where it can be discarded or
recycled. The main function of the process chamber evacuation pump
118 is controlled removal of gasses (including solvent) from the
process chamber 110. However, the process chamber evacuation pump
118 can also be used to clear the various gas lines of the
processing apparatus 100.
[0027] The processing apparatus 100 can include various feed gas
lines 108 and a gas box 109 where the gasses can be mixed and
conditioned (e.g., with heating or cooling; i.e., the gas box can
include heating and cooling elements, although not shown). The
vaporized solvent (and optionally a carrier gas) can be delivered
directly to the gas box 109 (as in FIG. 8) or can be delivered to
the gas box outlet 122, where it can mix with other gasses coming
from the gas box 109. As shown in FIG. 1, the vaporized solvent or
a mixture of the vaporized solvent and other gases from the gas box
109 enters the process chamber 110 through a plasma chamber
111.
[0028] The plasma chamber 111 can include an RF plasma source 112.
The RF plasma source 112 can be coupled to an inductive element to
generate an inductively coupled plasma in the plasma chamber 111. A
plasma can optionally be ignited in the plasma chamber 111 by
turning on the RF plasma source 112. When the RF plasma source 112
is turned on, the vaporized solvent molecules can dissociate in the
plasma and produce active species that assist in treating the
surface of the workpiece 116 (e.g., a semiconductor wafer). The
plasma chamber 111 can be separated from the process chamber 110
via a separation grid 113.
[0029] The resultant gas stream including the vaporized solvent and
potentially other gasses exits the plasma chamber 111 and enters
the process chamber 110. The process chamber 110 can include a seat
or pedestal 114 for holding a workpiece 116. The process chamber
110 can also have multiple pedestals 114 for holding multiple
workpieces 116, or a single pedestal 114 that can support multiple
workpieces 116, as shown in FIG. 1. The gas stream exiting the
plasma chamber 111 can pass through a separation grid 113 and enter
the process chamber 110 where the workpiece 116 is placed. The
separation grid 113 can serve to redistribute the gas flow evenly
over the surface of the workpiece 116 and also filter out charged
ions generated in the plasma. Therefore, the separation grid 113
can keep charged ions out of the process chamber 110 and allow
neutral radicals generated in a plasma to pass through.
[0030] The workpiece 116 in the process chamber can then be exposed
to a neutral radical stream that cleans the workpiece surface,
attacks photoresist, and removes post-etch residues. Alternatively,
the RF plasma source 112 can remain off In this case, the
workpiece(s) can be exposed to the vaporized solvent, or a mixture
of the vaporized solvent and other gasses. The surface of the
workpiece 116 can be cleaned via a chemical reaction that occurs
between the vaporized solvent and the workpiece surface. That is,
the vaporized solvent can react with photoresists and etch
residues, or other films or substances on the surface of the
workpiece 116.
[0031] FIG. 2 depicts a flow diagram of a method according to
example embodiments of the present disclosure. The method will be
described with reference to the apparatus embodiment of FIG. 1.
FIG. 2 depicts steps performed in a particular order for purposes
of illustration and discussion. Those of ordinary skill in the art,
using the disclosures provided herein, will understand that various
steps of any of the methods disclosed herein can be adapted,
expanded, rearranged, omitted, performed simultaneously, and/or
modified in various ways without deviating from the scope of the
present disclosure.
[0032] The method begins with the initiation of liquid solvent flow
to the vaporizer 105 and setting the desired flow rate (201). The
desired flow rate can be achieved using the solvent pump 121, the
mass or volumetric flow meter 106, and a controller. At this time,
the vaporized solvent can be discharged to the bypass line 107.
After the desired flow rate has been achieved, or the flow rate has
reached the desired steady state conditions, the bypass line 107
can be closed and the solvent vapor flow can proceed to the process
chamber (202). The solvent vapor (or a mixture of the vapor and
other gasses) can continue filling the process chamber 110 until
the pressure stabilizes at the desired chamber pressure (203). The
desired pressure can be obtained using a pressure gauge in the
process chamber or plasma chamber in combination with a pressure
controller (not shown). The workpiece 116 (e.g. wafer) can then be
exposed to the chemical vapor for a predetermined period of time
(204). After the exposure of the workpiece to the solvent vapor is
complete, solvent liquid flow to the vaporizer 105 can turned off
and the solvent vapor flow to the process chamber 110
correspondingly stops (205). The residue chemicals and the
remaining gasses in the process chamber 110 can then be evacuated
by the process chamber evacuation pump 118.
[0033] FIG. 3 depicts a flow diagram of a method according to
example embodiments of the present disclosure. The method will be
described with reference to the apparatus embodiment of FIG. 1.
FIG. 3 depicts steps performed in a particular order for purposes
of illustration and discussion. Those of ordinary skill in the art,
using the disclosures provided herein, will understand that various
steps of any of the methods disclosed herein can be adapted,
expanded, rearranged, omitted, performed simultaneously, and/or
modified in various ways without deviating from the scope of the
present disclosure.
[0034] The method begins with the initiation of liquid solvent flow
to the vaporizer 105 and setting the desired flow rate (301). To
initialize the system, the vaporized solvent can first be
discharged to the bypass line 107. After the desired flow rate has
been achieved, or the flow rate has reached the desired steady
state, the bypass line 107 can be closed and the solvent vapor flow
can proceed to the process chamber (302). The solvent vapor (or a
mixture of the vapor and other gasses) can continue filling the
process chamber 110 until the pressure stabilizes at the desired
chamber pressure (303). The workpiece 116 (e.g. wafer) can then be
exposed to the chemical vapor for a predetermined period of time
(304). Next, the RF source 112 can be engaged to strike plasma in
the plasma chamber 111, or the region above the separation grid 113
(305). The workpiece can then be exposed to the radicals created by
the plasma for a predetermined amount of time (306). Alternatively,
the RF source 112 can be engaged at an earlier time while the
solvent is filling the plasma chamber 111 and the process chamber
110 (step not shown). This alternative process step can induce a
greater number of solvent radicals in the process chamber 110.
Finally, after the workpiece processing, the RF source 112 and
solvent vapor flow can be stopped and the process chamber evacuated
(307).
[0035] FIG. 4 illustrates a processing apparatus 400 according to
example embodiments of the present disclosure. The solvent gas feed
line 101 is shown carrying a feed gas through a mass flow
controller 117 and to a solvent gas inlet line 124. The rate of
feed gas delivered can be adjusted and maintained using the mass
flow controller 117. A solvent storage receptacle bypass valve 123
can be included for bypassing feed gas around the solvent storage
receptacle 103.
[0036] In the embodiment of FIG. 4, the solvent storage receptacle
103 is an ampoule that holds a metered quantity of liquid solvent.
The solvent gas inlet line 124 can include a bubbler 115 that
disperses the feed gas within the liquid solvent, effectively
saturating the feed gas with solvent vapors. The solvent storage
receptacle outlet line 119 can be above the liquid level inside the
solvent storage receptacle 103 such that only solvent vapor (and
potentially feed gas) can continue down the solvent line 120. The
amount of solvent vapor that is fed into the solvent feed line 120
can also be controlled by adjusting the solvent vapor pressure
using a solvent temperature control component 125. The solvent
temperature control component 125 can be a coil that functions as a
heating and cooling element, allowing for both raising and lowering
the temperature of the solvent. Bidirectional solvent temperature
control allows for precise control of the solvent vapor pressure,
which is of primary importance in controlling the amount of solvent
vapor being delivered downstream. Otherwise, the processing
apparatus of FIG. 4 can operate in much the same manner, and assume
alternative configurations, as the other processing apparatuses
discussed herein.
[0037] FIG. 5 illustrates an example processing apparatus 500
according to example embodiments the present disclosure. The
processing apparatus 500 includes an ampoule (i.e., a solvent
storage receptacle) 103 that contains a liquid solvent. The ampoule
103 maintains the liquid solvent at a preset temperature. The
temperature can be maintained using a solvent temperature control
component 125. The solvent temperature control component 125 can be
in the form of a coil that conveys a fluid that heats or cools the
liquid solvent. Instead of a coil, the solvent temperature control
component 125 can be in the form of a shell or jacket that
encompasses the solvent storage receptacle 103. The temperature
control component can also include a temperature measurement device
(e.g., a thermometer or thermocouple) in combination with a
temperature controller. In the configuration of FIG. 5, the solvent
storage receptacle outlet line 119 is above the solvent liquid
level of the solvent ampoule 103. Therefore, the primary means of
conveying vaporized solvent to the process chamber 110 is
evaporation from the surface of the liquid solvent.
[0038] FIG. 6 illustrates an example processing apparatus 600
according to example embodiments of the present disclosure. The
processing apparatus 600 does not have a feed gas line integrated
within the solvent storage receptacle 103. The solvent storage
receptacle can maintain the liquid solvent at a present temperature
using a heating and cooling system 125. The temperature of the
liquid solvent can then determine the pressure within the solvent
storage receptacle 103, and the temperature can be raised if more
solvent flow is desired. A mass or volumetric flow meter 106, a
controller, and a control valve can be located on the solvent line
120 to control the solvent flow rate. The mass or volumetric flow
meter 106 can therefore control the amount and rate of vaporized
solvent going to the plasma chamber 111 and process chamber 120.
The purge gas line 102 can be used to clean out the solvent line
120 and bypass line 107, for example, during system
maintenance.
[0039] FIG. 7 illustrates an example processing apparatus 700
according to example embodiments the present disclosure. In the
example of FIG. 7, the solvent line 120 discharges directly into
the process chamber and bypasses the gas box 109, plasma chamber
111, RF source 112, and the separation grid 113.
[0040] In some embodiments, the solvent line 120 can be configured
to discharge into the process chamber via post-plasma injection in
a multi-plate separation grid 113. For instance, FIG. 8 depicts a
multi-plate separation grid 113 including a first grid plate 113.2
and a second grid plate 113.4 disposed in parallel relationship for
UV/ion filtering.
[0041] The first grid plate 113.2 and a second grid plate 113.4 can
be in parallel relationship with one another. The first grid plate
113.2 can have a first grid pattern having a plurality of holes.
The second grid plate 113.4 can have a second grid pattern having a
plurality of holes. The first grid pattern can be the same as or
different from the second grid pattern. Charged particles (e.g.,
ions) can recombine on the walls in their path through the holes of
each grid plate 113.2, 113.4 in the separation grid 113. Neutral
species (e.g., radicals) can flow relatively freely through the
holes in the first grid plate 113.2 and the second grid plate
113.4.
[0042] Subsequent to the second grid plate 113.2, the solvent line
120 can be configured to admit vaporized solvent into the particles
flowing through the separation grid 113. The vaporized solvent
and/or particles (e.g., neutral radicals) can pass through a third
grid plate 113.6 into the process chamber 110. More or fewer grid
plates can be used without deviating from the scope of the present
disclosure. In addition, the solvent line 120 can be configured to
admit vaporized solvent into the separation grid 113 at a location
below the separation grid 113.
[0043] FIG. 9 illustrates an example processing apparatus 800
according to example embodiments of the present disclosure. In FIG.
9, the solvent line 120 has a controller and two control valves 126
that can route vaporized solvent (and potentially carrier gasses)
directly into the process chamber 110, or upstream of the process
chamber (e.g., into the gas box 109, as shown), or a combination of
both. That is, the solvent line 120 can discharge into the process
chamber 110 as well as into the gas box 109, gas box outlet 122,
and the plasma chamber 111. The proportion of solvent (and
optionally carrier gas) being sent to each of the process chamber
110, the gas box 109, the gas box outlet 122, and the plasma
chamber 111 can therefore all be adjusted independently. That is,
the solvent line 120 can have lines and flow control mechanisms
(e.g., a controller, a control valve, and a mass/volume flow meter)
to meter solvent as well as a carrier gas to any combination of the
process chamber 110, the gas box 109, the gas box outlet 122, and
the plasma chamber 111. The discharge configurations of FIGS. 7 and
8 can be adapted to any of the embodiments discussed herein.
[0044] Embodiments of the present disclosure include processing
methods, specifically applicable to semiconductor workpieces, such
as semiconductor wafers. The methods can include placing the
workpiece into a process chamber 110, vaporizing a solvent and
feeding the vaporized solvent into the process chamber 110, and
exposing the workpiece to the vaporized solvent. Non-limiting
examples of solvents that can be applied include isopropyl alcohol
(IPA), acetone, methanol, N-methyl-2-pyrrolidone (NMP),
N-ethyl-2-pyrrolidone (NEP), dimethyl sulfoxide (DMSO), propylene
glycol methyl ether acetate (PGMEA), methyl ethyl ketone (MEK),
n-Butyl acetate (NBA), y-butyrolactone (GBL), propylene carbonate
(PC), triethylamine (TEA), and acetonitrile. Furthermore, mixtures
of solvents can also be applied and the solvents can be applied at
various pressures and partial pressures.
[0045] Different solvents and mixtures of solvents can also be
applied in series. For example, a workpiece can be exposed to a
first solvent (or solvent mixture) for a first period followed by a
second solvent for a second period. The workpiece can then be
exposed to a third solvent (or solvent mixture) for a third period,
and so on. Furthermore, the workpiece can be exposed to each
solvent or solvent mixture with or without incorporating a plasma
using an RF source 112.
[0046] The solvent can be carried to the process chamber 110 using
one or more carrier gasses. The carrier gas can be an inert feed
gas (e.g., noble gasses, etc.) or one or more of the carrier gasses
can be active in the process chemistry by synergizing with the
solvent or other process gasses emanating from the gas box 109.
Specific examples of inter and/or carrier gases include helium,
nitrogen, and/or argon.
[0047] The solvent can be put in gaseous form by feeding liquid
solvent to a vaporizer 105. The amount of solvent fed to the
process chamber 110 can be controlled using metering pumps 121,
mass flow meters 106 (e.g., on the feed gas line 101 or solvent
line 120), volumetric flow meters (e.g., on the feed gas line 101
or solvent line 120), logic controllers, control valves, and
pressure gauges, as well as combinations thereof. Prior to feeding
the solvent to the process chamber 120, the solvent flow rates can
be stabilized or brought to steady state using a bypass line 107.
After the solvent flow rate has stabilized, a control valve on the
bypass line 107 can be closed and the solvent routed to the process
chamber 110 where it can be exposed to the workpiece 116.
[0048] The solvent can be administered to the process chamber in
various ways. That is, the solvent line 120 can direct the solvent
to various locations within the processing apparatus such as the
process chamber 110, the gas box 109, the gas box outlet 122, and
the plasma chamber 111. Furthermore, the processing apparatus can
incorporate all of these options into a single system and control
the amount of solvent sent to each location using controllers,
control valves, and mass and volumetric flow meters. Furthermore,
an RF source 112 can be engaged to strike a plasma (with optionally
incorporating various gasses from the various gas feed lines 108)
before the solvent is administered, while the solvent is being
administered, or after the solvent has been administered but is
still residing within the process chamber 110. Engaging the RF
source 112 allows for dissociating the vaporized solvent into
active species that assist in the process.
[0049] The solvent can pass through a separation grid 113 prior to
entering the process chamber 110. The separation grid 113 can
disperse the vaporized solvent (and potentially other gasses) as it
enters the process chamber 110 such that the gasses are evenly
exposed to the workpiece 116. When the RF source 112 is engaged,
the separation grid 113 can capture charged ions, allowing only
neutral radicals to pass through to the process chamber 110 and
keeping charged radicals out.
[0050] Methods can include exposing the workpiece 116 to a
plasma-affected vaporized solvent (i.e., a vaporized solvent that
has been exposed to a plasma and/or has been ignited by an RF
source) and exposing the workpiece 116 to a non-plasma-affected
vaporized solvent (i.e., a vaporized solvent that has not been
exposed to a plasma and has not been ignited by an RF source). The
method can also be reversed. That is, the workpiece 116 can be
exposed to a non-plasma-affected vaporized solvent followed by a
plasma-affected vaporized solvent. The vaporized solvent can also
be mixed with one or more other gasses or plasmas (e.g., hydrogen-,
nitrogen-, and/or oxygen-containing plasmas) and then be exposed to
the workpiece 116.
[0051] The pressure in the process chamber 110 can be held constant
or varied while the solvent is exposed to the workpiece 116. That
is, the pressure in the process chamber 110 can be controlled to
rise, fall, or fluctuate over time. Further, the partial pressures
of the solvent and other gasses can be controlled.
[0052] The liquid solvent in the solvent storage receptacle 103 can
be held at a constant temperature. The temperature of the liquid
solvent is especially critical when the solvent vapor pressure is
the primary or sole means of conveying solvent to the process
chamber 110.
[0053] Therefore, the solvent storage receptacle 103 can include a
temperature control component for raising or lowering the
temperature of the solvent. The temperature control component can
include a coil 125 in which a heating or cooling fluid flows, or
the coil 125 can include an electric heating element. The
temperature control component can also take the form of a shell
that encompasses the solvent storage receptacle 103 and contains
and electric heating element or temperature control fluid. The
solvent storage receptacle 103 may further have an insulating
jacket to assist in controlling temperature.
[0054] The solvent storage receptacle 103 can take multiple forms
including a metal or glass liquid tank, or a compressed gas tank.
The solvent storage receptacle 103 can also be a metered ampoule
that delivers a specific volume or mass of liquid solvent to the
process chamber 110. An ampoule can be particularly useful in
situations where the solvent is delivered downstream by heating and
evaporating the liquid solvent within the solvent storage
receptacle 103. The solvent can also be delivered downstream by
dispersing (e.g., using a bubbler 115) a carrier gas within the
liquid solvent or passing a carrier gas over the liquid solvent as
it evaporates. The amount of solvent delivered can be controlled in
this scenario, at least in part, by measuring and metering the flow
rate (e.g., using a mass or volumetric flow meter and controller
106) of the carrier gas prior to the carrier gas making contact
with the solvent.
[0055] As discussed above, the solvent can be delivered directly to
the process chamber 110. Various other gases can also be delivered
to the process chamber 110 in combination with the solvent.
Furthermore, the solvent can be delivered directly to the process
chamber 110 while various other gasses are delivered to the process
chamber 110 in plasma form after passing through the plasma chamber
111. In addition and/or in the alternative, a fraction of the
solvent can be diverted to the process chamber 110 while the
remainder of the solvent passes through the plasma chamber 111 and
is exposed to the RF source 112.
[0056] The process chamber 110 and/or workpiece can be heated while
the solvent is being exposed to the workpiece 116. For example, the
process chamber and/or workpiece can be maintained at a temperature
range of from about 50.degree. C. to about 400.degree. C.
[0057] After the solvent has been exposed to the workpiece 116, the
process chamber 110 can be evacuated using the process chamber
evacuation pump 118. A purge gas can also be used to help empty the
process chamber 110. However, the process pump 118 can also be used
to maintain a constant pressure within the process chamber 110 as
fresh solvent and potentially other gasses are introduced to the
process chamber 110. The fresh solvent and other gasses can be
introduced continuously (at a constant flow rate) or in periodic
bursts (e.g., the process chamber is charged with fresh solvent
every 10 minutes).
[0058] Instead of a single plasma chamber, the processing apparatus
100 can have multiple plasma chambers each having an RF source. For
example, FIGS. 1, 4, 5, 6, 7, and 9 show a processing apparatus
having dual plasma chambers 111 and dual RF sources 112. This can
alloy for greater process efficiency as multiple workpieces can be
treated in the process chamber 110 at once, helping to conserve the
footprint of the process equipment and improving overall
throughout.
[0059] While the present subject matter has been described in
detail with respect to specific example embodiments thereof, it
will be appreciated that those skilled in the art, upon attaining
an understanding of the foregoing may readily produce alterations
to, variations of, and equivalents to such embodiments.
Accordingly, the scope of the present disclosure is by way of
example rather than by way of limitation, and the subject
disclosure does not preclude inclusion of such modifications,
variations and/or additions to the present subject matter as would
be readily apparent to one of ordinary skill in the art.
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