U.S. patent application number 10/115682 was filed with the patent office on 2003-10-09 for cleaning ceramic surfaces.
This patent application is currently assigned to Applied Materials, Inc.. Invention is credited to Chen, Hui, Han, Nianci, Lu, Danny Chien, Shih, Hong, Tang, Hui, Wang, Dan, Wang, Xikun, Xu, Li, Zhang, Yang.
Application Number | 20030190870 10/115682 |
Document ID | / |
Family ID | 28673815 |
Filed Date | 2003-10-09 |
United States Patent
Application |
20030190870 |
Kind Code |
A1 |
Shih, Hong ; et al. |
October 9, 2003 |
Cleaning ceramic surfaces
Abstract
Method and apparatus for cleaning ceramic surfaces of parts
used, for example, and without limitation, in semiconductor
processing equipment. In particular, one embodiment of the present
invention is a method for cleaning a ceramic part that includes
steps of: (a) treating the surface using one or more first
mechanical processes; (b) treating the surface using one or more
chemical processes; (c) plasma conditioning the surface; and (d)
treating the surface using one or more second mechanical
processes.
Inventors: |
Shih, Hong; (Walnut Creek,
CA) ; Lu, Danny Chien; (Milpitas, CA) ; Han,
Nianci; (San Jose, CA) ; Wang, Xikun;
(Sunyvale, CA) ; Chen, Hui; (San Jose, CA)
; Tang, Hui; (San Jose, CA) ; Xu, Li; (San
Jose, CA) ; Zhang, Yang; (Albany, CA) ; Wang,
Dan; (San Jose, CA) |
Correspondence
Address: |
APPLIED MATERIALS, INC.
2881 SCOTT BLVD. M/S 2061
SANTA CLARA
CA
95050
US
|
Assignee: |
Applied Materials, Inc.
|
Family ID: |
28673815 |
Appl. No.: |
10/115682 |
Filed: |
April 3, 2002 |
Current U.S.
Class: |
451/39 |
Current CPC
Class: |
B08B 7/0035 20130101;
B08B 3/08 20130101; B08B 7/04 20130101 |
Class at
Publication: |
451/39 |
International
Class: |
B24C 001/00 |
Claims
What is claimed is:
1. A method for cleaning a part having a ceramic surface which
comprises steps of: treating the surface using one or more first
mechanical processes; treating the surface using one or more
chemical processes; plasma conditioning the surface; and treating
the surface using one or more second mechanical processes.
2. The method of claim 1 wherein the step of treating the surface
using one or more first mechanical processes includes
bead-blasting.
3. The method of claim 1 wherein the step of plasma conditioning
comprises inductively coupling energy to a plasma in a chamber and
exposing the surface to the plasma in the chamber.
4. The method of claim 3 which further includes forming the plasma
utilizing precursors that include an inert gas.
5. The method of claim 4 wherein the inert gas comprises Ar.
6. The method of claim 4 wherein the precursors further include a
reactive chemical.
7. The method of claim 6 wherein the reactive chemical comprises
Cl.sub.2.
8. The method of claim 6 wherein the reactive chemical comprises
BCl.sub.3.
9. The method of claim 1 wherein the step of plasma conditioning
comprises capacitively coupling energy to a plasma in a chamber and
exposing the surface to the plasma in the chamber.
10. The method of claim 9 wherein the step of exposing comprises
disposing the surface in a plasma chamber, and the step of
capacitively coupling includes forming the plasma utilizing
precursors that include an inert gas.
11. The method of claim 10 wherein the inert gas comprises Ar.
12. The method of claim 10 wherein the precursors further include a
reactive chemical.
13. The method of claim 1 wherein the step of plasma conditioning
comprises generating a plasma, flowing the plasma into a chamber,
and exposing the surface to the plasma in the chamber.
14. The method of claim 13 wherein the step of generating includes
exposing a gas to microwaves.
15. The method of claim 13 wherein the step of generating includes
exposing a gas to RF energy.
16. The method of claim 1 wherein the step of treating the surface
using one or more first mechanical processes comprises steps of:
rinsing the surface using pressurized deionized water; and
propelling CO.sub.2 pellets against the surface.
17. The method of claim 1 wherein the step of treating the surface
using one or more chemical processes comprises steps of: dipping
the part in NH.sub.4OH:H.sub.2O.sub.2:H.sub.2O; and dipping the
part in HF:HNO.sub.3:H.sub.2O.
18. The method of claim 1 wherein the step of treating the surface
using one or more second mechanical processes comprises steps of:
propelling CO.sub.2 snow against the surface; and ultrasonically
cleaning the surface using deionized water.
19. A method for cleaning a part having a ceramic surface which
comprises steps of: treating the surface using one or more first
mechanical processes; treating the surface using one or more
chemical processes; exposing the surface to
H.sub.2SO.sub.4:H.sub.2O.sub.2; and treating the surface using one
or more second mechanical processes.
20. The method of claim 19 wherein the step of treating the surface
using one or more first mechanical processes includes
bead-blasting.
21. A method for cleaning a part having a ceramic surface which
comprises steps of: treating the surface using one or more first
mechanical processes; treating the surface using one or more
chemical processes; exposing the surface to NMD-3; and treating the
surface using one or more second mechanical processes.
Description
TECHNICAL FIELD OF THE INVENTION
[0001] One or more embodiments of the present invention pertain to
method and apparatus for cleaning ceramic surfaces of parts used,
for example, and without limitation, in semiconductor processing
equipment.
BACKGROUND OF THE INVENTION
[0002] Because of the development of 300 mm semiconductor
processing equipment (for example, and without limitation, etching
equipment), and the shrinkage of device features to dimensions of
0.15 .mu.m, or less, defect and particle performance of such
semiconductor processing equipment becomes an important factor in
achieving good production device yield. As is well known, to
improve defect and particle performance (and hence yield),
semiconductor processing equipment must be cleaned (prior to
installation, and after use in production). At the same time,
because the cost of semiconductor integrated circuit manufacturing
factories ("fabs") is going up, semiconductor processing equipment
productivity is also important. However, time taken to clean
equipment to improve yield tends to reduce productivity.
[0003] One way to achieve and maintain high productivity and high
yield, among other things, is to increase mean wafers between clean
("MWBC"). To increase MWBC, it is well known to bead-blast ceramic
surfaces of parts (such as, for example, and without limitation, a
ceramic dome, a chamber lid, a focus ring, and other ceramic
process kit parts) used in semiconductor processing equipment. It
is believed that surface roughness improves the ability of process
residues to adhere to the ceramic surfaces of the parts. It is also
believed that this ability improves the defect and particle
performance of the parts, and hence the defect and particle
performance of the semiconductor processing equipment in which they
are used. In addition to bead-blasting, wet cleaning methods have
also been developed to eliminate defect and particle performance
issues that arise with the use of parts having ceramic
surfaces.
[0004] Although the above-described methods have been successfully
applied in conjunction with parts having ceramic surfaces for use
in 200 mm semiconductor processing equipment, defects and particles
performance issues have arisen, among other places, in conjunction
with parts having ceramic surfaces for use in 300 mm semiconductor
processing equipment (and, in particular, with such parts for use
in 300 mm semiconductor processing equipment used to etch small
feature sizes).
[0005] In light of the above, there is a need in the art for method
and apparatus for cleaning ceramic surfaces of parts used, for
example, in semiconductor processing equipment.
SUMMARY OF THE INVENTION
[0006] One or more embodiments of the present invention
advantageously satisfy the above-identified need in the art, and
provide a method and apparatus for cleaning ceramic surfaces of
parts used, for example, in semiconductor processing equipment. In
particular, one embodiment of the present invention is a method for
cleaning a ceramic part that comprises steps of: (a) treating the
surface using one or more first mechanical processes; (b) treating
the surface using one or more chemical processes; (c) plasma
conditioning the surface; and (d) treating the surface using one or
more second mechanical processes.
BRIEF DESCRIPTION OF THE FIGURE
[0007] FIG. 1 shows a block diagram of a cleaning method that is
carried out in accordance with one embodiment of the present
invention, which cleaning method is used to clean ceramic surfaces
of new parts and used parts that require further bead-blasting;
[0008] FIG. 2 shows a block diagram of a cleaning method that is
carried out in accordance with one embodiment of the present
invention, which cleaning method is used to clean ceramic surfaces
of parts having AlF.sub.3 deposited thereon;
[0009] FIG. 3 shows a block diagram of a cleaning method that is
carried out in accordance with one embodiment of the present
invention, which cleaning method is used to clean ceramic surfaces
of parts not having AlF.sub.3 deposited thereon;
[0010] FIG. 4 shows a block diagram of a method that is carried out
in accordance with one embodiment of the present invention, which
method is used to handle parts having ceramic surfaces at a factory
prior to installation; and
[0011] FIGS. 5-8 show pictorial representations of four embodiments
of a plasma chamber used to provide plasma conditioning in
accordance with one or more embodiments of the present
invention.
DETAILED DESCRIPTION
[0012] FIG. 1 shows a block diagram of a cleaning method that is
carried out in accordance with one embodiment of the present
invention, which cleaning method is used to clean ceramic surfaces
of new parts and used parts that require further bead-blasting. As
shown at step 100 of FIG. 1, as-fired (i.e., new) parts having a
ceramic surface, or used parts having a ceramic surface, are
bead-blasted (in accordance with any one of a number of methods
that are well known to those of ordinary skill in the art) to
provide a predetermined surface roughness. For example, in one
embodiment, surface roughness may be in a range from about 20
R.sub.a to about 120 R.sub.a. In practice, the predetermined
surface roughness may vary depending on particular processing
conditions to which a part is exposed (for example, semiconductor
processing conditions such as, without limitation, a type and
thickness of residue deposited thereon). Appropriate ranges of
values of surface roughness may be determined routinely by one of
ordinary skill in the art without undue experimentation.
[0013] Next, as shown at step 110 of FIG. 1, the bead-blasted part
may be rinsed, for example, using pressurized deionized water ("DI
water"), to remove, for example, certain floating particles
produced by the bead-blasting. The pressure used (for example, and
without limitation, in one embodiment, about 50 psi) should be
sufficient to enable removal of a predetermined amount of the
floating particles without damaging the part. Appropriate ranges of
pressure to use for such a rinse step may be determined routinely
by one of ordinary skill in the art without undue experimentation.
Next, as shown at step 120 of FIG. 1, the part may be dried (in
accordance with any one of a number of methods that are well known
to those of ordinary skill in the art), for example, and without
limitation, in one embodiment, using filtered air or N.sub.2.
[0014] Next, as shown at step 130 of FIG. 1, in one embodiment, the
ceramic surface of the part may be exposed to CO.sub.2 pellets that
are propelled against the ceramic surface (in accordance with any
one of a number of methods that are well known to those of ordinary
skill in the art). For example, and without limitation, in one
embodiment, air may be used as a propellant. It is believed that
this step removes particles by physical bombardment, and that it
aids in removing polymer residues by a combination of thermal shock
and physical bombardment. In particular, it is believed that the
temperature of the surface of the part may be reduced (for example,
to temperatures as low as -70.degree. C.) by use of the CO.sub.2
pellets. Further, it is believed that the reduced temperature, and
a thermal coefficient of expansion mismatch between the polymer
residue and the ceramic surface, enables the residue to be removed
by the bombardment. Appropriate ranges of values of: (a) the size
of the CO.sub.2 pellets; and (b) the force at which they are
propelled may be determined routinely by one of ordinary skill in
the art without undue experimentation. Next, as shown at step 140
of FIG. 1, the part may be rinsed, for example, using DI water (in
accordance with any one of a number of methods that are well known
to those of ordinary skill in the art).
[0015] Next, as shown at step 150 of FIG. 1, the part may be dipped
in NH.sub.4OH:H.sub.2O.sub.2:H.sub.2O (in accordance with any one
of a number of methods that are well known to those of ordinary
skill in the art). For example, in one embodiment, this step may:
(a) use relative amounts of NH.sub.4OH:H.sub.2O.sub.2:H.sub.2O of
(about 1):(about 1):(about 2) by weight; (b) be performed at a
temperature below about 50.degree. C.; and (c) last for about one
(1) hour to about two (2) hours. Appropriate ranges of values of:
(a) the relative amounts of NH.sub.4OH, H.sub.2O.sub.2, and
H.sub.2O; (b) the temperature of the dip; and (c) the length of
time of the dip may be determined routinely by one of ordinary
skill in the art without undue experimentation. It is believed that
NH.sub.4OH may be useful in removing metal contaminants, and that
H.sub.2O.sub.2 may be useful in removing organic contaminants.
Next, as shown at step 160 of FIG. 1, the part may be rinsed, for
example, using DI water (in accordance with any one of a number of
methods that are well known to those of ordinary skill in the
art).
[0016] Next, as shown at step 170 of FIG. 1, the part may be dipped
in HF:HNO.sub.3:H.sub.2O (in accordance with any one of a number of
methods that are well known to those of ordinary skill in the art).
For example, in one embodiment, this step may: (a) use relative
amounts of HF:HNO.sub.3:H.sub.2O of (about 1):(about 1):(about 10)
by weight; (b) be performed at a temperature of about 20.degree.
C.; and (c) last for about one (1) hour. Appropriate ranges of
values of: (a) the relative amounts of HF, HNO.sub.3, and H.sub.2O;
(b) the temperature of the dip; and (c) the length of time of the
dip may be determined routinely by one of ordinary skill in the art
without undue experimentation. It is believed that HF may be useful
in removing silicon based materials (such as, for example, silicon
oxide, glass, and so forth), and that HNO.sub.3 may be useful in
removing metal oxides. Next, as shown at step 180 of FIG. 1, the
part is rinsed, for example, in DI water (in accordance with any
one of a number of methods that are well known to those of ordinary
skill in the art).
[0017] The inventors have discovered that so-called "dangling
particles" produced by bead-blasting may be a source of defect and
particle performance issues for parts having ceramic surfaces,
especially when such parts are used in semiconductor processing
equipment used to fabricate integrated circuits on 300 mm wafers.
In addition, the inventors have discovered that these "dangling
particles" may be removed by utilizing: (a) a chemically enhanced
clean step; and/or (b) a plasma conditioning step that provides
physical bombardment and/or a chemical reaction in a gas phase
environment (for example, and without limitation, by utilizing a
high density plasma). A chemically enhanced clean step in
accordance with one embodiment of the present invention proceeds as
follows. As shown at step 190 of FIG. 1, the part may be dipped in
H.sub.2SO.sub.4:H.sub.2O.sub.2 (in accordance with any one of a
number of methods that are well known to those of ordinary skill in
the art). For example, in one embodiment, this step may: (a) use
relative amounts of H.sub.2SO.sub.4:H.sub.2O.sub.2 of (about
1):(about 1) by weight; (b) be performed at a temperature of about
140.degree. C.; and (c) last for about one (1) to about two (2)
hours. Appropriate ranges of values of: (a) the relative amounts of
H.sub.2SO.sub.4, and H.sub.2O.sub.2; (b) the temperature of the
dip; and (c) the length of time of the dip may be determined
routinely by one of ordinary skill in the art without undue
experimentation. Next, as shown at step 200 of FIG. 1, the part is
rinsed, for example, in DI water (in accordance with any one of a
number of methods that are well known to those of ordinary skill in
the art). Then, as shown in FIG. 1, processing continues at step
230.
[0018] A plasma conditioning step in accordance with one embodiment
of the present invention proceeds as follows. As shown at step 210
of FIG. 1, the part is baked to remove water remaining from step
180 of FIG. 1 (in accordance with any one of a number of methods
that are well known to those of ordinary skill in the art). For
example, in one embodiment, this step may: (a) entail baking the
part in an oven; (b) be performed at a temperature of about
110.degree. C.; and (c) last for about one (1) hour. Appropriate
ranges of values of: (a) the temperature of the bake; and (b) the
length of time of the bake may be determined routinely by one of
ordinary skill in the art without undue experimentation. Next, as
shown at step 220 of FIG. 1, the part is plasma conditioned in a
plasma chamber (embodiments of which are described in detail
below). In accordance with one embodiment of the present invention,
the plasma chamber utilizes an RF source of electromagnetic energy
to generate a plasma therein, for example, an inductively coupled
plasma--typically a high density plasma. Further, as set forth
below, such a plasma chamber can operate at a wide range of
pressures, for example, and without limitation, pressures such as,
for example, from about 100 mT to below about 50 mT. In addition,
in accordance with one embodiment of the present invention, a
plasma is formed using: (a) an inert gas such as, for example, and
without limitation, argon (Ar) to provide a physical bombardment
mechanism for cleaning; and/or (b) one or more reactive gases such
as, for example, and without limitation, chlorine (Cl.sub.2) or
BCl.sub.3 to provide a chemically reactive mechanism for cleaning.
The particular type of gas to provide the chemically reactive
mechanism may be chosen depending on the type of ceramic surface to
be cleaned, and the processes applications in which it is used. In
addition, as will be explained below, it is advantageous for the
plasma chamber to include adapters to enable plasma conditioning of
parts used in both 200 mm and 300 mm processing chambers. In
accordance with this embodiment, plasma conditioning step 220 can
last for about thirty (30) minutes to about several hours,
depending on the process applications and materials under
treatment. Lastly, appropriate ranges of values of: (a) plasma
chamber pressure; (b) gases used to form the plasma; (c) the length
of time of plasma conditioning; (d) the energy and frequency of the
source of electromagnetic energy used to create the plasma; and (e)
plasma chamber temperature may be determined routinely by one of
ordinary skill in the art without undue experimentation.
[0019] In accordance with another embodiment of the present
invention, the plasma chamber utilizes an RF source of
electromagnetic energy to generate a plasma therein, for example, a
capacitively coupled plasma. Further, as set forth below, such a
plasma chamber can operate at a wide range of pressures, for
example, and without limitation, pressures such as, for example,
from about 1 T to about 50 T. In addition, in accordance with one
embodiment of the present invention, a plasma is formed using: (a)
an inert gas such as, for example, and without limitation, argon
(Ar) to provide a physical bombardment mechanism for cleaning;
and/or (b) one or more reactive gases such as, for example, and
without limitation, chlorine (Cl.sub.2) or BCl.sub.3 to provide a
chemically reactive mechanism for cleaning. The particular type of
gas to provide the chemically reactive mechanism may be chosen
depending on the type of ceramic surface to be cleaned, and the
processes applications in which it is used. In accordance with this
embodiment, plasma conditioning step 220 can last for about thirty
(30) minutes to about several hours, depending on the process
applications and materials under treatment. Lastly, appropriate
ranges of values of: (a) plasma chamber pressure; (b) gases used to
form the plasma; (c) the length of time of plasma conditioning; (d)
the energy and frequency of the source of electromagnetic energy
used to create the plasma; and (e) plasma chamber temperature may
be determined routinely by one of ordinary skill in the art without
undue experimentation.
[0020] In accordance with yet another embodiment of the present
invention, the plasma chamber utilizes a remote plasma generator to
generate a plasma which then flows into the plasma chamber.
Further, as set forth below, such a plasma chamber can operate at a
wide range of pressures. In addition, in accordance with one
embodiment of the present invention, a plasma is formed using one
or more reactive gases such as, for example, and without
limitation, chlorine (Cl.sub.2) or BCl.sub.3 to provide a
chemically reactive mechanism for cleaning. The particular type of
gas to provide the chemically reactive mechanism may be chosen
depending on the type of ceramic surface to be cleaned, and the
processes applications in which it is used. In accordance with this
embodiment, plasma conditioning step 220 can last for about thirty
(30) minutes to about several hours, depending on the process
applications and materials under treatment. Lastly, appropriate
ranges of values of: (a) plasma chamber pressure; (b) gases used to
form the plasma; (c) the length of time of plasma conditioning; (d)
the number distribution of various plasma species; and (e) plasma
chamber temperature may be determined routinely by one of ordinary
skill in the art without undue experimentation.
[0021] Next, as shown at step 230 of FIG. 1, the part may be
exposed to a stream of, for example, filtered air or N.sub.2 (in
accordance with any one of a number of methods that are well known
to those of ordinary skill in the art). This step may be used to
remove excess water if the precursor step was step 200, and this
step may be used to remove accumulated particles if the precursor
step was step 220. Next, as shown at step 240 of FIG. 1, the part
is transferred to a cleanroom, for example, and without limitation,
a Class 100 cleanroom, for any further processing. Then, as further
shown at step 240 of FIG. 1, small particles may be removed. For
example, the part may be exposed to CO.sub.2 snow (in accordance
with any one of a number of methods that are well known to those of
ordinary skill in the art). Appropriate ranges of values of: (a)
snow temperature; and (b) the force at which the snow is propelled
may be determined routinely by one of ordinary skill in the art
without undue experimentation. Us Next, as shown at step 250 of
FIG. 1, the part may be rinsed, for example, in DI water (in
accordance with any one of a number of methods that are well known
to those of ordinary skill in the art). Then, the part may be
exposed to a stream of, for example, filtered air or N.sub.2 to
remove excess water. Next, as shown at step 260 of FIG. 1, a
surface roughness measurement may be made in accordance with any
one of a number of methods that are well known to those of ordinary
skill in the art. If the surface does not have a predetermined
degree of roughness (see above), then the part may be returned to
step 100 of FIG. 1 for further bead-blasting.
[0022] Next, as shown at step 270 of FIG. 1, the part may be
cleaned by high purity DI water ultrasonic cleaning (in accordance
with any one of a number of methods that are well known to those of
ordinary skill in the art). For example, in one embodiment, this
step may: (a) utilize DI water whose purity is such that it has a
resistivity of about 12 M.OMEGA. or higher; (b) be performed at a
temperature of about 50.degree. C.; and (c) last for about two (2)
hours. Appropriate ranges of values of: (a) the purity of the DI
water; (b) the temperature of the cleaning step; and (c) the length
of time of the cleaning step may be determined routinely by one of
ordinary skill in the art without undue experimentation. In
addition, in one embodiment, an endpoint for this cleaning step may
be determined by using a liquid particle counter ("LPC")
measurement (in accordance with any one of a number of methods that
are well known to those of ordinary skill in the art). The endpoint
is signaled when the number of particles measured by LPC falls
below a predetermined amount. Appropriate ranges of values of: (a)
the temperature of the cleaning step; and (b) the length of time of
the cleaning step may be determined routinely by one of ordinary
skill in the art without undue experimentation.
[0023] Next, as shown at step 280 of FIG. 1, the part is rinsed,
for example, in high purity DI water (in accordance with any one of
a number of methods that are well known to those of ordinary skill
in the art). For example, in one embodiment, this step may utilize
DI water whose purity is such that it has a resistivity of about 12
M.OMEGA. or higher. Then, the part may be exposed to a stream of,
for example, N.sub.2 (in accordance with any one of a number of
methods that are well known to those of ordinary skill in the art)
to remove excess water. Appropriate ranges of values of the purity
of the DI water may be determined routinely by one of ordinary
skill in the art without undue experimentation. Next, as shown at
step 290 of FIG. 1, the part is baked to remove water remaining
after step 280 (in accordance with any one of a number of methods
that are well known to those of ordinary skill in the art). For
example, in one embodiment, this step may: (a) entail baking the
part in an oven; (b) be performed at a temperature of about
150.degree. C.; and (c) last for about two (1) hours. Appropriate
ranges of values of the temperature of the bake, and the length of
time of the bake may be determined routinely by one of ordinary
skill in the art without undue experimentation.
[0024] Next, as shown at step 300 of FIG. 1, a surface particle
measurement is made after the part has cooled down to about room
temperature (in accordance with any one of a number of methods that
are well known to those of ordinary skill in the art is made). For
example, the measurement may be made using a QIII particle counter.
For example, in one embodiment, this measurement detects particles
of size about 0.3 .mu.m or larger. If the number of particles is
higher than a predetermined amount, then the part may be returned
to step 180 of FIG. 1. Next, as shown at step 310 of FIG. 1, the
part is exposed to a stream of filtered, pure, dry air or N.sub.2
(in accordance with any one of a number of methods that are well
known to those of ordinary skill in the art). For example, in one
embodiment, the purity of the air or N.sub.2 are such that any
particles have a size of about <0.1 .mu.m or smaller.
Appropriate ranges of values of the purity of the air or N.sub.2
may be determined routinely by one of ordinary skill in the art
without undue experimentation. Lastly, as shown at step 320 of FIG.
1, the part is vacuum sealed and packaged (in accordance with any
one of a number of methods that are well known to those of ordinary
skill in the art).
[0025] As one can readily appreciate from the description above,
steps 100, 110, 120, 130, 140, 160, 180, 200, 210, 230, 240, 250,
270, 280, 290, and 310 of FIG. 1 are mechanical processes, and
steps 150, 170, and 190 of FIG. 1 are chemical processes. In
further embodiments of the present invention, one or more of the
above-described chemical steps may further include, or be replaced
by, other chemical steps such as one or more of an H.sub.2O.sub.2
dip (it is believed that this process step may be useful in
removing organic contaminants); an HCl:H.sub.2O.sub.2 dip (it is
believed that this process step may be useful in removing metal
contaminants), an HF dip (it is believed that this process step may
be useful in removing silicon based materials--such as, for
example, silicon oxide, glass, and so forth); an
HNO.sub.3:H.sub.2O.sub.2 dip (it is believed that this process step
may be useful in removing metal oxides and organic contaminants);
an isopropyl alcohol (IPA) dip; and an acetone dip.
[0026] The above-described cleaning process may be used to process
any number of types of parts having ceramic surfaces, including,
without limitation, parts having surfaces comprised of alumina,
YAG, Si, SiC, AlN, Si.sub.3N.sub.4, Spinel, ZrO.sub.2; and parts
having chemical vapor deposited ceramic coatings, plasma spray
ceramic coatings, and anodized ceramic coatings.
[0027] The process described above in conjunction with FIG. 1 may
also be utilized to clean "used" parts having ceramic surfaces
which do not require bead-blasting by omitting step 100 of FIG. 1.
Here, the term "used" parts refers to parts that, for example, have
been used to process wafers in a semiconductor processing
equipment, by omitting step 100.
[0028] FIG. 2 shows a block diagram of a cleaning method that is
carried out in accordance with one embodiment of the present
invention, which cleaning method is used to clean ceramic surfaces
of parts having AlF.sub.3 deposited thereon. As one can readily
appreciate from this, many of the steps of this cleaning process
are the same as steps of the cleaning process shown in FIG. 1 and
described above (and hence have the same numeric designations). As
such, the following will only describe steps that are different
from those shown in FIG. 1. As shown at step 400 of FIG. 2, the
part may be dipped in H.sub.2O.sub.2:H.sub.2O (in accordance with
any one of a number of methods that are well known to those of
ordinary skill in the art). For example, in one embodiment, this
step may: (a) use a concentration of H.sub.2O.sub.2:H.sub.2O of
about 30 wt % H.sub.2O.sub.2; (b) be performed at a temperature
below about 50.degree. C.; and (c) last for about one (1) hour.
Appropriate ranges of values of: (a) the concentration of
H.sub.2O.sub.2; (b) the temperature of the dip; and (c) the length
of time of the dip may be determined routinely by one of ordinary
skill in the art without undue experimentation. Next, as shown at
step 410 of FIG. 2, the part may be rinsed, for example, in DI
water (in accordance with any one of a number of methods that are
well known to those of ordinary skill in the art). Then, the part
may be exposed to a stream of air to remove excess water (in
accordance with any one of a number of methods that are well known
to those of ordinary skill in the art).
[0029] Next, as shown at step 420 of FIG. 2, the part may be
cleaned (in accordance with any one of a number of methods that are
well known to those of ordinary skill in the art) using, for
example, acetone, isopropyl alcohol (IPA), and a brush, for
example, a Scotch Brite.TM. brush (a brush that is sold by 3M
Corporation) at about room temperature. Appropriate ranges of
values of: (a) the temperature; and (b) the concentrations of the
acetone and IPA may be determined routinely by one of ordinary
skill in the art without undue experimentation.
[0030] Lastly, as shown at step 430 of FIG. 2, the part may be
dipped (in accordance with any one of a number of methods that are
well known to those of ordinary skill in the art) in an NMD-3
solution (NMD-3 is a mixture of tetramethyl ammonium hydroxide
[N(CH.sub.3).sub.4OH] and water that is available from Tokyo Ohka
Kogyo Co., Ltd. through, for example, Ohka America, Inc. of
Milpitas, Calif., that is believed to remove AlF.sub.x). For
example, in one embodiment, this step may: (a) use an about 2.38 wt
% NMD-3 solution; (b) be performed at a temperature of about room
temperature or higher (for example, and without limitation, at a
temperature of about 50.degree. C.; and (c) last for about two (2)
hours. Appropriate ranges of values of: (a) the concentration of
NMD-3; (b) the temperature of the dip; and (c) the length of time
of the dip may be determined routinely by one of ordinary skill in
the art without undue experimentation. Alternatively, to remove
AlF.sub.x, step 430 of FIG. 2 may be replaced by a bake step (in
accordance with any one of a number of methods that are well known
to those of ordinary skill in the art). For example, this step may
use an oven bake above a temperature where AlF.sub.3 is volatile.
Since AlF.sub.3 is volatile above about 550.degree. C. to about
575.degree. C., in one embodiment, one may use a bake temperature
of about 800.degree. C.
[0031] As one can readily appreciate from the description above,
steps 110, 120, 410, 140, 160, 200, 230, 240, 250, 270, 280, 290,
and 310 of FIG. 2 are mechanical processes, and steps 400, 420,
150, and 430 of FIG. 2 are chemical processes. In further
embodiments of the present invention, the mechanical steps may
include use of a CO.sub.2 ice pellet cleaning and/or a CO.sub.2
snow cleaning. In still further embodiments of the present
invention, one or more of the above-described chemical steps may
further include, or be replaced by, other chemical steps such as
one or more of an HF:HNO.sub.3:H.sub.2O dip (it is believed that
this process step may be useful in removing silicon based
materials, and metal oxides); an H.sub.2SO.sub.4:H.sub.2O.sub.2
dip; an HCl:H.sub.2O.sub.2 dip (it is believed that this process
step may be useful in removing metal contaminants), an HF dip (it
is believed that this process step may be useful in removing
silicon based materials--such as, for example, silicon oxide,
glass, and so forth); and an HNO.sub.3:H.sub.2O.sub.2 dip (it is
believed that this process step may be useful in removing metal
oxides and organic contaminants).
[0032] FIG. 3 shows a block diagram of a cleaning method that is
carried out in accordance with one embodiment of the present
invention, which cleaning method is used to clean ceramic surfaces
of parts not having AlF.sub.3 deposited thereon. As one can readily
appreciate from this, many of the steps of this cleaning process
are the same as steps of the cleaning process shown in FIG. 1 and
described above (and hence have the same numeric designations). As
such, the following will only describe steps that are different
from those shown in FIG. 1. As shown at step 500 of FIG. 3, the
part may be dipped in H.sub.2O.sub.2:H.sub.2O (in accordance with
any one of a number of methods that are well known to those of
ordinary skill in the art). For example, in one embodiment, this
step may: (a) use a concentration of H.sub.2O.sub.2:H.sub.2O of
about 30 wt % H.sub.2O.sub.2; (b) be performed at a temperature
below about 50.degree. C.; and (c) last for about one (1) hour.
Appropriate ranges of values of: (a) the concentration of
H.sub.2O.sub.2; (b) the temperature of the dip; and (c) the length
of time of the dip may be determined routinely by one of ordinary
skill in the art without undue experimentation. Next, as shown at
step 510 of FIG. 3, the part may be rinsed, for example, in DI
water (in accordance with any one of a number of methods that are
well known to those of ordinary skill in the art). Then, the part
may be exposed to a stream of air to remove excess water (in
accordance with any one of a number of methods that are well known
to those of ordinary skill in the art). Next, as shown at step 520
of FIG. 3, the part may be cleaned (in accordance with any one of a
number of methods that are well known to those of ordinary skill in
the art) using, for example, acetone, IPA, and a brush, for
example, a Scotch Brite.TM. brush at about room temperature.
Appropriate ranges of values of: (a) the temperature; and (b) the
concentrations of the acetone and IPA may be determined routinely
by one of ordinary skill in the art without undue
experimentation.
[0033] As one can readily appreciate from the description above,
steps 110, 120, 510, 140, 160, 230, 240, 250, 270, 280, 290, and
310 of FIG. 3 are mechanical processes, and steps 500, 520, and 150
of FIG. 3 are chemical processes. In further embodiments of the
present invention, the mechanical steps may include use of a
CO.sub.2 ice pellet cleaning and/or a CO.sub.2 snow cleaning. In
still further embodiments of the present invention, one or more of
the above-described chemical steps may further include, or be
replaced by, other chemical steps such as one or more of an
HF:HNO.sub.3:H.sub.2O dip (it is believed that this process step
may be useful in removing silicon based materials, and metal
oxides); an H.sub.2SO.sub.4:H.sub.2O.sub.2 dip; an
HCl:H.sub.2O.sub.2 dip (it is believed that this process step may
be useful in removing metal contaminants), an HF dip (it is
believed that this process step may be useful in removing silicon
based materials--such as, for example, silicon oxide, glass, and so
forth); and an HNO.sub.3:H.sub.2O.sub.2 dip (it is believed that
this process step may be useful in removing metal oxides and
organic contaminants).
[0034] FIG. 4 shows a block diagram of a method that is carried out
in accordance with one embodiment of the present invention, which
method is used to handle parts having ceramic surfaces at a factory
prior to installation. As shown at step 600 of FIG. 4, a package of
parts having a ceramic surface is opened in a cleanroom. Next, as
shown at step 610 of FIG. 4, the part may be rinsed, for example,
in DI water (in accordance with any one of a number of methods that
are well known to those of ordinary skill in the art). Next, as
shown at step 620 of FIG. 4, the part may be cleaned by a high
purity DI water ultrasonic cleaning process (in accordance with any
one of a number of methods that are well known to those of ordinary
skill in the art). For example, in one embodiment, this step may:
(a) utilize DI water whose purity is such that it has a resistivity
of about 12 M.OMEGA. or higher; (b) be performed at a temperature
of about 50.degree. C.; and (c) last for about two (2) hours.
Appropriate ranges of values of: (a) the purity of the DI water;
(b) the temperature of the cleaning step; and (c) the length of
time of the cleaning step may be determined routinely by one of
ordinary skill in the art without undue experimentation. Next, as
shown at step 630 of FIG. 4, the part may be rinsed, for example,
in high purity DI water (in accordance with any one of a number of
methods that are well known to those of ordinary skill in the art).
Then, the part may be exposed to a stream of, for example, N.sub.2
(in accordance with any one of a number of methods that are well
known to those of ordinary skill in the art). This may be used to
blow off excess water. Next, as shown at step 640 of FIG. 4, the
part may be baked to remove water remaining after step 630 of FIG.
4 (in accordance with any one of a number of methods that are well
known to those of ordinary skill in the art). For example, in one
embodiment, this step may: (a) entail baking the part in an oven;
(b) be performed at a temperature of about 150.degree. C.; and (c)
last for about two (1) hours. Appropriate ranges of values of: (a)
the temperature of the bake; and (b) the length of time of the bake
may be determined routinely by one of ordinary skill in the art
without undue experimentation. Next, as shown at step 650 of FIG.
4, after the part has cooled down, it may be exposed to a stream
of, for example, filtered, high purity N.sub.2 (in accordance with
any one of a number of methods that are well known to those of
ordinary skill in the art). For example, in one embodiment, the
purity of the N.sub.2 is such that any particles have a size of
about or <0.1 .mu.m. This step may be used to remove accumulated
particles. An appropriate range of values of the purity of the
N.sub.2 may be determined routinely by one of ordinary skill in the
art without undue experimentation. Next, as shown at step 660, the
part is either vacuum sealed or transferred directly to the
semiconductor processing equipment in which it is to be installed.
Lastly, as shown at step 670, in one embodiment, the part may be
exposed to a stream of, for example, N.sub.2, and it may be wiped
with IPA.
[0035] FIGS. 5 and 6 show pictorial representations of two
embodiments of a plasma chamber used to provide plasma conditioning
in accordance with one or more embodiments of the present
invention. In particular, FIG. 5 shows chamber 700 used to plasma
condition "shaped" ceramic dome 710. As shown in FIG. 5, plasma
chamber 700 comprises cathode base structure 720, chamber body 730,
pedestal 740, O-ring 750, adapter 760, O-ring 770, RF coil 780,
O-ring 790, coil power supply 791, cathode power supply 792, and
controller 795. Cathode base structure 720 provides a cathode in a
manner that is well known to those of ordinary skill in the art,
and supports parts having ceramic surfaces mounted on pedestal 740
thereon. O-ring 790 seals the interior of chamber 700, and such a
seal may be fabricated in accordance with any one of a number of
methods that are well known to those of ordinary skill in the art.
O-rings 750 and 770 seal the interior of chamber 700, and are
disposed between chamber body 730 and adapter 760, and between
adapter 760 and ceramic dome 710, respectively. Adapter 760 is
shaped to be used with both a dome from 200 mm semiconductor
processing equipment and a dome from 300 mm semiconductor
processing equipment. As such, for use with a dome from 200 mm
equipment, adapter 760 will extend into the interior of chamber
700, since chamber 700 will ordinarily be sized for use with a dome
from 300 mm equipment.
[0036] RF coil 780 is fabricated in accordance with any one of a
number of methods that are well known to those of ordinary skill in
the art to produce a substantially inductively coupled plasma,
typically, a high density plasma, in chamber 700. Advantageously,
the use of a high density plasma better enables control between
amounts of physical bombardment and chemical reaction in the plasma
conditioning process. Coil power supply 791 is fabricated in
accordance with any one of a number of methods that are well known
to those of ordinary skill in the art to cause RF coil 780 to
generate a plasma in the interior of chamber 700. Appropriate
ranges of frequency and power may be determined routinely by one or
ordinary skill in the art without undue experimentation. Cathode
power supply 792 is fabricated in accordance with any one of a
number of methods that are well known to those of ordinary skill in
the art to produce a bias voltage on pedestal 740. Coil power
supply 791 and cathode power supply 792 operate in response to
signals from controller 795. As is well known, various amounts of
RF energy and cathode bias, as well as the particular gases and
pressures thereof, and temperature within chamber 7000, control the
amount of physical bombardment and chemical reaction occurring in
chamber 700. Gas inlets (not shown) enable gas to flow into chamber
700. Controller 795 is also connected to gas input controllers (not
shown, but fabricated in accordance with any one of a number of
methods that are well known to those of ordinary skill in the art),
and to a chamber exhaust mechanism (not shown, but fabricated in
accordance with any one of a number of methods that are well known
to those of ordinary skill in the art) to control the pressure
inside chamber 700. In addition, controller 795 is also connected
to a heating mechanism disposed, for example, in pedestal 740 (not
shown, but fabricated in accordance with any one of a number of
methods that are well known to those of ordinary skill in the art),
to help control (along with a measure of the physical bombardment)
the temperature inside chamber 700.
[0037] FIG. 6 shows chamber 800 used to plasma condition flat
ceramic dome 810. As shown in FIG. 6, plasma chamber 800 is similar
in all respects (other than dome 710) to chamber 700. In
particular, chamber 800 comprises cathode base structure 820,
chamber body 830, pedestal 840, O-ring 850, adapter 860, O-ring
870, RF coil 880, O-ring 890, coil power supply 891, cathode power
supply 892, and controller 895. It should be appreciated by those
of ordinary skill in the art that similarly number parts in FIGS. 5
and 6 provide similar functionality as that described above for
chamber 700.
[0038] It should also be appreciated by those of ordinary skill in
the art that chambers 700 and 800 shown in FIGS. 5 and 6,
respectively, may also be used to plasma condition parts other than
domes. Such parts may be placed on pedestals 740 and 840,
respectively, or they may be disposed on appliances that may be
fabricated in accordance with any one of a number of methods that
are well known to those of ordinary skill in the art.
[0039] FIG. 7 shows chamber 1000 used to plasma condition parts
disposed therein. As shown in FIG. 7, plasma chamber 1000 comprises
cathode base structure 1020, chamber body 1030, pedestal 1040,
O-ring 1090, top-plate power supply 1091, cathode power supply
1092, and controller 1095. Cathode base structure 1020 provides a
cathode in a manner that is well known to those of ordinary skill
in the art, and supports parts having ceramic surfaces mounted on
pedestal 1040 therein. O-ring 1090 seals the interior of chamber
1000, and such a seal may be fabricated in accordance with any one
of a number of methods that are well known to those of ordinary
skill in the art.
[0040] Top-plate 1080 is fabricated in accordance with any one of a
number of methods that are well known to those of ordinary skill in
the art to produce a substantially capacitively coupled plasma in
chamber 1000. For example, as shown in FIG. 7, gas flows from line
1057 into chamber 1000 through gas distribution box 1065. The gas
may enter chamber 1000 through channels in top-plate 1080 (for
example, top-plate 1080 may comprise a showerhead), or through gas
inlets. Appropriate gas distribution mechanisms can be fabricated
in accordance with any one of a number of methods that are well
known to those of ordinary skill in the art. Top-plate power supply
1091 is fabricated in accordance with any one of a number of
methods that are well known to those of ordinary skill in the art
to cause top-plate 1080 to generate a plasma in the interior of
chamber 1000. Appropriate ranges of frequency and power may be
determined routinely by one or ordinary skill in the art without
undue experimentation. Cathode power supply 1092 is fabricated in
accordance with any one of a number of methods that are well known
to those of ordinary skill in the art to produce a bias voltage on
pedestal 1040. Appropriate ranges of frequency and power may be
determined routinely by one or ordinary skill in the art without
undue experimentation. Top-plate power supply 1091 and cathode
power supply 1092 operate in response to signals from controller
1095. As is well known, various amounts of RF power and cathode
bias, as well as particular gases and pressures thereof, and
temperature within chamber 1000, control the amount of physical
bombardment and chemical reaction occurring in chamber 1000.
Controller 1095 is also connected to gas input controllers (not
shown, but fabricated in accordance with any one of a number of
methods that are well known to those of ordinary skill in the art),
and to a chamber exhaust mechanism (not shown, but fabricated in
accordance with any one of a number of methods that are well known
to those of ordinary skill in the art) to control the pressure
inside chamber 1000. In addition, controller 1095 is also connected
to a heating mechanism disposed, for example, in pedestal 1040 (not
shown, but fabricated in accordance with any one of a number of
methods that are well known to those of ordinary skill in the art),
to help control (along with a measure of the physical bombardment)
the temperature inside chamber 1000. Lastly, parts to be
conditioned may be placed on pedestal 1040, or they may be disposed
on appliances that may be fabricated in accordance with any one of
a number of methods that are well known to those of ordinary skill
in the art.
[0041] FIG. 8 shows chamber 1100 used to plasma condition parts
disposed therein. As shown in FIG. 8, plasma chamber 1100 comprises
pedestal base structure 1120, chamber body 1130, pedestal 1140,
O-ring 1190, remote plasma generator 1157, heater power supply
1177, and controller 1195. Pedestal base structure 1120 supports
parts having ceramic surfaces mounted on pedestal 1140 thereon.
O-ring 1190 seals the interior of chamber 1100, and such a seal may
be fabricated in accordance with any one of a number of methods
that are well known to those of ordinary skill in the art.
[0042] As shown in FIG. 8, remote plasma generator 1157 generates a
plasma in accordance with any one of a number of methods that are
well known to those of ordinary skill in the art. For example, in
accordance with one embodiment of remote plasma generator 1157, a
gas flows through a tube that is exposed to microwaves output from
a microwave generator in accordance with any one of a number of
methods that are well known to those of ordinary skill in the art.
A plasma is formed which flows through gas line 1159 into chamber
1100 through gas distribution box 1153. The plasma may enter
chamber 1000 through channels in top-plate 1180 (for example,
top-plate 1180 may comprise a showerhead), or through gas inlets.
Appropriate gas distribution mechanisms can be fabricated in
accordance with any one of a number of methods that are well known
to those of ordinary skill in the art. An appropriate distance
between remote plasma generator 1157 and gas distribution box 1153
may be determined routinely by one of ordinary skill in the art
without undue experimentation to enable a predetermined number
distribution of various plasma species to be present inside chamber
1000. In addition, appropriate ranges of microwave frequency and
power, and gas pressure in remote plasma generator 1157 may be
determined routinely by one or ordinary skill in the art without
undue experimentation.
[0043] In accordance with an alternative embodiment of remote
plasma generator 1157, a gas flows into an entrance channel in a
toroidal tube. A coil is wound about at least a portion of the
tube, and the coil is energized by RF energy in accordance with any
one of a number of methods that are well known to those of ordinary
skill in the art to generate a plasma in the toroidal tube. The
plasma gas flows out of an exit channel in the toroidal tube,
through gas line 1159, and into chamber 1100 through gas
distribution box 1153. Appropriate ranges of RF frequency and
power, and gas pressure in remote plasma generator 1157 may be
determined routinely by one or ordinary skill in the art without
undue experimentation. As is well known, the number distribution of
various plasma species, as well as the particular gases used and
the pressures thereof, as well as temperature within chamber 1100,
control the amount of chemical reaction occurring in chamber
1100.
[0044] Controller 1195 is also connected to gas input controllers
for remote plasma generator 1157 (not shown, but fabricated in
accordance with any one of a number of methods that are well known
to those of ordinary skill in the art), and to a chamber exhaust
mechanism (not shown, but fabricated in accordance with any one of
a number of methods that are well known to those of ordinary skill
in the art) to control the pressure inside chamber 1100. In
addition, controller 1195 is also connected to heating power supply
1187 disposed, for example, in pedestal 1140 (not shown, but
fabricated in accordance with any one of a number of methods that
are well known to those of ordinary skill in the art), to help
control the temperature inside chamber 1100. Lastly, parts to be
conditioned may be placed on pedestal 1140, or they may be disposed
on appliances that may be fabricated in accordance with any one of
a number of methods that are well known to those of ordinary skill
in the art without undue experimentation.
[0045] It should be understood by those of ordinary skill in the
art that all the power supplies described above include apparatus
to provide impedance matching in accordance with any one of a
number of methods that are well known to those of ordinary skill in
the art.
[0046] Those skilled in the art will recognize that the foregoing
description has been presented for the sake of illustration and
description only. As such, it is not intended to be exhaustive or
to limit the embodiments of the present invention to the precise
form disclosed. For example, further embodiments of the present
invention exist wherein plasma conditioning is performed by use of
plasma sprays or plasma guns that are fabricated in accordance with
any one of a number of methods that are well known to those of
ordinary skill in the art. In addition, although one or more
embodiments of the present invention have been described in the
context of parts used in semiconductor processing equipment,
embodiments of the present invention are not limited to parts used
in such equipment. Further, the term semiconductor processing
equipment relates to equipment which processes semiconductor wafers
or glass substrates, to equipment used to inspect wafers and/or
substrates, and to equipment used to manufacture masks used to
manufacture integrated circuits and/or optical components.
* * * * *