U.S. patent application number 11/472017 was filed with the patent office on 2007-07-26 for apparatus for shielding process chamber port having dual zone and optical access features.
This patent application is currently assigned to LAM RESEARCH CORPORATION. Invention is credited to Fangli J. Hao, Leonard Sharpless, Harmeet Singh.
Application Number | 20070169704 11/472017 |
Document ID | / |
Family ID | 38284304 |
Filed Date | 2007-07-26 |
United States Patent
Application |
20070169704 |
Kind Code |
A1 |
Hao; Fangli J. ; et
al. |
July 26, 2007 |
Apparatus for shielding process chamber port having dual zone and
optical access features
Abstract
A port in a window member provides first access to a process
chamber interior for gas injection and second optical access for
process analysis and measurement. Plasma-induced etching and
deposition in a bore of a gas injector integral with the window
member is reduced by a grounded shield surrounding an access
region, and coatings reduce particle flaking from walls of a first
clear optical aperture of the injector and from a second clear
optical aperture of a gas and optical access fitting,. The shield
surrounds the region, and is configured with couplers to hold the
gas and optical access fitting to the window member for access to
the injector. The couplers compress seals so that a gas bore in the
fitting is sealed to a plenum of the injector, while allowing
optical access into the chamber through the first clear optical
aperture and the second clear optical aperture.
Inventors: |
Hao; Fangli J.; (Cupertino,
CA) ; Sharpless; Leonard; (Fremont, CA) ;
Singh; Harmeet; (Fremont, CA) |
Correspondence
Address: |
MARTINE PENILLA & GENCARELLA, LLP
710 LAKEWAY DRIVE
SUITE 200
SUNNYVALE
CA
94085
US
|
Assignee: |
LAM RESEARCH CORPORATION
Fremont
CA
|
Family ID: |
38284304 |
Appl. No.: |
11/472017 |
Filed: |
June 20, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11341079 |
Jan 26, 2006 |
|
|
|
11472017 |
Jun 20, 2006 |
|
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Current U.S.
Class: |
118/733 ;
156/345.1 |
Current CPC
Class: |
H01J 37/32623 20130101;
H01J 37/32477 20130101 |
Class at
Publication: |
118/733 ;
156/345.1 |
International
Class: |
H01L 21/306 20060101
H01L021/306; C23C 16/00 20060101 C23C016/00 |
Claims
1. A window for protecting an access region for access to a process
chamber from an electric field generated adjacent to the process
chamber window, the window comprising: a window member configured
with outer and chamber sides and a groove extending from the outer
side into the member parallel to the axis, the groove defining a
first section of the access region to be protected from the
electric field, the window member being further configured with a
clear optical aperture having an annular wall configured with an
axial length between the outer side and the chamber side, the clear
optical aperture being partly surrounded by the groove, the clear
optical aperture being further configured with a diameter; and a
coating on the annular wall of the clear optical aperture, the
annular wall with the coating having an inner coating diameter that
is substantially the same as a value of the axial length of the
clear optical aperture, the material from which the coating is
fabricated being taken from the group consisting of cerium oxide,
zirconium oxide, yttria-stabilized zirconia, thermally-sprayed
aluminum oxide, yttrium oxide, and yttrium oxide having pores,
wherein the pores are sealed with a material taken from the group
consisting of methacylate ester and polymer.
2. A process chamber window as recited in claim 1, wherein the
window member is further configured from one piece of ceramic.
3. A process chamber window as recited in claim 1, wherein the
window member is further configured with an annular gas plenum and
a plurality of nozzles, each of the nozzles being connected to the
annular gas plenum.
4. A process chamber window as recited in claim 1, wherein the
chamber side of the window member is configured with a flat
surface.
5. A process chamber window as recited in claim 3, wherein the
chamber side of the window member is configured with a projection
defined by an axially-extending surface and a flat surface parallel
to the chamber side, the nozzles intersecting the axially-extending
surface.
6. A multi-function process chamber window assembly for protecting
an access region for access to a process chamber from an electric
field generated adjacent to the process chamber window, for
admitting at least one gas to the process chamber, and for
providing optical access to the chamber, the assembly comprising: a
three-dimensional shield having a length extending parallel to an
access region axis and being fabricated from material adapted to
substantially block the electric field; a window member configured
with respect to the access region axis, the member being configured
with outer and chamber sides and a groove extending from the outer
side into the member, the groove extending parallel to the axis,
the groove defining a first section of the access region to be
protected from the electric field, the groove being configured to
receive a portion of the shield to protect the first section of the
access region from the electric field, the groove receiving the
portion of the shield so that the shield extends out of the groove
and away from the outer side so that a second section of the access
region is defined within the shield, the shield protecting the
second section from the electric field, the window member being
further configured with a first clear optical aperture defined by a
first annular wall extending co-axially with the axis and
configured with an axial length between the outer side and the
chamber side, the first clear optical aperture being partly
surrounded by the groove, the first clear optical aperture being
further configured with a diameter for clear optical access; and a
first coating on the first annular wall, the first annular wall
with the coating having an inner coating diameter that is
substantially the same as a value of the axial length of the first
clear optical aperture, the coating protecting the first clear
optical aperture from effects of the electric field so that the
protection extends past the shield in the groove to the chamber
side of the window member, the material from which the first
coating is fabricated being taken from the group consisting of
cerium oxide, zirconium oxide, yttria-stabilized zirconia,
thermally-sprayed aluminum oxide, yttrium oxide, and yttrium oxide
having pores, wherein the pores are sealed with a material taken
from the group consisting of methacylate ester and polymer.
7. An assembly as recited in claim 6, the assembly further
comprising: a multi-function fitting received within the second
section of the access region defined by the shield for protection
from the electric field, the fitting being configured with a second
clear optical aperture having a second annular wall extending
co-axially with the axis and aligned with the coated first clear
optical aperture to supply gas to the first clear optical aperture
and allow clear optical access to the chamber through the first and
second clear optical apertures.
8. An assembly as recited in claim 7, wherein: the window member is
configured with a plenum extending from the outer side into the
member and with a plurality of nozzles extending from the plenum to
the chamber side to supply gas to the chamber; and the fitting is
further configured with a gas supply bore extending parallel to the
axis and aligned with the plenum.
9. An assembly as recited in claim 8, the assembly further
comprising a seal structure between the fitting and the window
member.
10. An assembly as recited in claim 9, wherein: the shield is
configured with opposite ends, each of the ends being configured
with a coupler, one coupler securing the shield to the window
member with the shield in the groove, the other coupler securing
the fitting to the shield so that the fitting is urged toward the
window member; and the seal structure is configured so that in
response to the other coupler urging the fitting toward the window
member the seal structure seals to the window member so that gas
flows from the gas supply bore into the plenum separately from the
first and second clear optical apertures and gas flows from the
second clear optical aperture into the first clear optical aperture
separately from the gas supply bore and the plenum.
11. An assembly as recited in claim 7, wherein the fitting is
configured with an end, the assembly further comprising: a first
seal structure between the end of the fitting and the window
member; and wherein the end is configured with a seat adjacent to
the seal structure and co-axial with the access region axis; the
assembly further comprising an optical window received in the seat
and a second seal structure between the seat and the optical window
to prevent gas from leaking past the second optical aperture while
allowing optical access through the second clear optical aperture
and the first clear optical aperture into the chamber.
12. An assembly as recited in claim 11, wherein the fitting is
further configured with at least one access port in the second
annular wall to provide access to the optical window, the port
being located on a side of the optical window that is away from the
window member.
13. An assembly as recited in claim 7, wherein the second clear
optical aperture is configured so that the second annular wall is
open from a first end that is adjacent to the window member to a
second end spaced from the window member, the second end of the
fitting being further configured with a sealing seat, the assembly
further comprising: the assembly further comprising an optical
window received in the sealing seat and a second seal structure
between the seat and the optical window to prevent gas from leaking
past the second optical aperture while allowing optical access
through the second clear optical aperture and the first clear
optical aperture into the chamber; the spacing of the second end
from the window member enabling location of the optical window
where the strength of the electric field is substantially reduced
as compared to the electric field strength adjacent to the process
chamber window.
14. An assembly as recited in claim 13, the assembly further
comprising: a second coating on the second annular wall, the second
coating extending from the first end for a distance about equal to
the diameter of the second annular wall; and a third coating on the
second annular wall, the second coating extending from the second
end for a distance about equal to the diameter of the second
annular wall; the second and third coatings being fabricated from
the same material as the first coating.
15. An assembly as recited in claim 6, wherein: the window member
is configured with an annular plenum extending from the outer side
into the member and with a plurality of nozzles extending from the
annular plenum to the chamber side to supply gas to the chamber;
the assembly further comprises a multi-function fitting received
within the second section of the access region defined by the
shield for protection from the electric field, the fitting being
configured with a second clear optical aperture having a second
annular wall extending co-axially with the axis and aligned with
the coated first clear optical aperture to supply gas to the first
clear optical aperture and allow clear optical access to the
chamber through the first and second clear optical apertures, the
fitting is further configured with a gas supply bore extending
parallel to the axis and aligned with the annular plenum; the
shield is configured with opposite ends, each of the ends being
configured with a coupler, one coupler securing the shield to the
window member with the shield in the groove, the other coupler
securing the fitting to the shield so that the fitting is urged
toward the window member, the end configured with the one coupler
being configured with a seat that is co-axial with the access
region axis; and the assembly further comprises a first seal
structure between the window member and the one end of the fitting
that is configured with the one coupler, the first seal structure
sealing the gas supply bore to the plenum, an optical window
received in the seat, a second seal structure between the seat and
the optical window to prevent gas from leaking past the second
optical aperture while allowing optical access through the second
clear optical aperture and the first clear optical aperture into
the chamber.
16. An assembly as recited in claim 15, wherein: the fitting is
further configured with a second gas supply bore extending relative
to the axis to supply gas to the first clear optical aperture; the
first seal structure seals the second gas supply bore to the first
clear optical aperture when the fitting is urged toward the window
member while allowing the optical access through the second clear
optical aperture and the first clear optical aperture into the
chamber.
17. A multi-function process chamber window assembly for protecting
an access region for access to a process chamber from an electric
field generated adjacent to the process chamber window while
providing at least two gas inlets to the process chamber and
allowing optical access to the chamber, the assembly comprising: an
integrated shield and gas supply unit for protecting the access
region from the electric field, the unit having a thin
three-dimensional protrusion at a first end and being configured
with a body that is thicker than the protrusion, the body being
further configured to extend from the first end parallel to an
access region axis to a second end, the body being further
configured with a first annular wall defining a unit clear aperture
extending along the axis from the first end to the second end, the
body being further configured with a first gas supply bore
extending parallel to the axis and intersecting the unit clear
optical aperture adjacent to the first end, the body being further
configured with a first coupler, the unit being fabricated from
material adapted to substantially block the electric field so that
the unit clear optical aperture is protected from the electric
field; a window member configured with respect to the access region
axis, the member being configured with outer and chamber sides and
a groove extending from the outer side into the member, the groove
extending parallel to the axis, the groove being configured to
receive the thin protrusion to protect a first section of the
access region from the electric field, the member being further
configured with a second coupler configured to cooperate with the
first coupler to hold the protrusion in the groove with the unit
extending away from the outer side of the member so that a second
section of the access region is defined by and is protected by the
body from the electric field, the window member being further
configured with a window member clear optical aperture having a
second annular wall extending co-axially with the axis and
configured with an axial length between the outer side and the
chamber side, the window member clear optical aperture being partly
surrounded by the thin protrusion received in the groove, the
window member clear optical aperture being further configured with
a diameter; and a coating on the second annular wall, the second
annular wall with the coating having an inner coating diameter that
is substantially the same as a value of the axial length of the
window member clear optical aperture, the coating protecting the
window member clear optical aperture from the electric field, the
material from which the coating is fabricated being taken from the
group consisting of cerium oxide, zirconium oxide,
yttria-stabilized zirconia, thermally-sprayed aluminum oxide,
yttrium oxide, and yttrium oxide having pores, wherein the pores
are sealed with a material taken from the group consisting of
methacylate ester and polymer.
18. An assembly as recited in claim 17, wherein: the body of the
unit is further configured with a second gas supply bore extending
parallel to the axis and to the first end; and the window member is
further configured with a plenum extending from the outer side into
the member, plenum receiving gas from the second gas supply bore,
the window member being configured with a plurality of nozzles that
are spaced around the axis and receive the gas from the plenum.
19. An assembly as recited in claim 17, wherein: the body of the
unit is further configured with a pair of co-axial annular
recesses, a first of the recesses is between the unit clear optical
aperture and the second gas supply bore, a second of the recesses
is between the second gas supply bore and the annular groove; the
assembly further comprises a seal member received in each of the
recesses in opposition to the outer side of the window member; and
with the couplers holding the protrusion in the groove the outer
side of the window member is held opposed to the seal members in
the recesses to seal the second gas supply bore to the plenum and
seal the unit clear optical aperture to the window member clear
optical aperture while allowing optical access through the unit
clear optical aperture and the window member clear optical aperture
into the chamber.
20. An assembly as recited in claim 17, wherein: the second end of
the body of the integrated unit is further configured with a seat;
the assembly further comprises an optical window configured for
reception in the seat and a clamp for holding the optical window in
the seat; and the second end is spaced from the first end to locate
the seat for the optical window where a strength of the electric
field is substantially reduced as compared to an electric field
strength adjacent to the process chamber window.
Description
RELATED APPLICATION
[0001] This application is a continuation-in-part of U.S. patent
application Ser. No. 11/341,079, filed Jan. 26, 2006 for "Apparatus
For Shielding Process Chamber Port", in the names of Fangli J. Hao,
John E. Daugherty, and Allan K. Ronne (the "Prior Application").
The disclosure of the Prior Application is incorporated by
reference. The benefit of the filing date of the Prior Application
is claimed under 35 U.S.C. Section 120.
BACKGROUND
[0002] 1. Field of the Invention
[0003] The present invention relates generally to semiconductor
manufacturing and, more particularly, to apparatus for shielding
access regions of process chambers from electrical fields, wherein
the access regions allow access to semiconductor manufacturing
chambers, the electric fields are applied to the chambers adjacent
to the access regions, and access openings in the access regions
provide access for exemplary gas injectors and process analysis and
measurement tools.
[0004] 2. Description of the Related Art
[0005] Vacuum processing chambers have been used for etching
materials from substrates and for deposition of materials onto
substrates, and the substrates have been semiconductor wafers, for
example. U.S. Pat. No. 6,230,651 to Ni et al. issued May 15, 2001
and assigned to Lam Research Corporation, the assignee of the
present application, is incorporated herein by reference and
illustrates an opening, or port, in a dielectric window at a top of
a processing chamber to provide access to an interior of the
processing chamber, for etching and other processing of
semiconductor substrates, for example. For large diameter
substrates, center gas injection was said to ensure uniform etching
and deposition, for example, thus improving the access to such
processing chambers.
[0006] However, as industry standards have increased, further
improvements are required to provide even better access to such
processing chambers. For example, there is a need to monitor the
processes in the chambers, which requires chamber access in
addition to access for gas supply. When the monitoring relies on
optical data, a clear optical aperture must extend through the
dielectric window. Difficulties arise, however, when the clear
optical aperture is physically open to the chamber, because plasma
may form in the clear optical aperture. Such plasma formation
relates to a threshold electric field strength required to initiate
a plasma, which threshold strength is based on gas pressure in and
the diameter of a passage, or bore, used to supply the gas to the
chamber. Plasma formation in a gas supply bore is generally reduced
by reducing the diameter of the bore because the gas pressure tends
to be controlled by process requirements. However, analysis by the
applicants of the present application indicates that when there is
dual use of a clear optical aperture (i.e., use for both optical
and gas supply functions) the dual use presents conflicting
requirements. That is, for the aspect of facilitating monitoring
the optical data, there is a need to increase the diameter of the
clear optical aperture. For example, in providing optical access
for spectroscopic observation of chamber processes, the diameter of
the clear optical aperture must generally be not less than about
one-half inch, for example, and it is highly desirable to use an
aperture as large as possible. This diameter may be described as a
minimum diameter that is required to enable proper access to the
optical data that originates in the chamber, and is referred to
herein as the "minimum diameter of the clear optical aperture".
This analysis also indicates that for the gas supply aspect of the
dual use there is a need for a relatively small diameter
(significantly less than 0.5 inch) of each gas bore for gas supply
to the chamber, for avoiding plasma formation, for example. This
analysis also indicates that to facilitate the dual use, an optical
window must be used to seal the clear optical aperture so as to
maintain a vacuum in the processing chamber, and that the optical
window should be mounted at a location at which the strength of the
electric field is substantially reduced, to prevent sputtering of
the optical window (which creates aluminum-containing
contamination), and to prevent deposition onto the optical window.
Thus, applicants' analysis indicates that there is not only the
minimum diameter of the clear optical aperture in conflict with the
need for small diameter gas bores, but a minimum length of the
clear optical aperture necessary to avoid such contamination and
damage to the optical window that facilitates the dual use.
[0007] This exemplary 0.5 inch minimum diameter of the clear
optical aperture compares to gas bore passages of 0.4 mm provided
in shielded gas inlets described, for example, in U.S. Pat. No.
6,500,299, issued 12/3/102 to Mett, et al. Although multiple ones
of such passages are provided through grains of dielectric
materials such as ceramics, with the 0.4 mm diameter size, such
passages are not suitable for providing clear optical access for
the exemplary spectroscopic observation of chamber processes.
Moreover, to mount such passages of a gas bore inside a metal cup
and to insert the cup in the side wall of a process chamber as
described in the Mett et al. Patent, would undesirably subject the
metal cup to the plasma in the chamber, for example, and introduce
problems in sealing the metal cup to the wall of the process
chamber.
[0008] In view of the foregoing, there is a need for apparatus
providing further improvements in accessing processing chambers.
The need is for improved ways to provide multiple access (e.g., gas
supply and optical access) to a process chamber. This need includes
providing such access when the optical access is subject to the
conflicting requirements of a relatively large minimum diameter of
the clear optical aperture (for the optical function) and of a
relatively small diameter of one or more gas bores for gas supply
to the chamber (for avoiding plasma formation), for example.
SUMMARY
[0009] Broadly speaking, embodiments of the present invention fill
these needs by providing apparatus for shielding a process chamber
port having dual zone and optical access features, the shielding
being from electrical fields, wherein the access region allows
access to a semiconductor manufacturing chamber, the electric
fields are applied to the chamber adjacent to the access region,
and access openings in the access regions provide access for
exemplary gas injectors and process analysis and measurement tools.
Such apparatus may include configurations of an access region of a
process chamber to allow dual supply of process gas to the chamber,
and to provide a first clear optical aperture for optical access
through a window of the chamber. Such apparatus may also provide a
combination of protection of a dual gas supply fitting and the
first clear optical aperture from the electric field established by
the coil that surrounds the first clear optical aperture and the
fitting. A shield may be configured to extend into the window to
provide such protection for a first section of the first clear
optical aperture with a remaining second section of the first clear
optical aperture extending toward the processing chamber. The
remaining section may be protectively coated to provide such
protection from the electric field and provide the minimum length
of the clear optical aperture. A second clear optical aperture is
provided in the fitting to extend the first aperture away from the
electric field. The shield and additional coatings may protect the
second clear optical aperture from the electric field, and an
optical window may close the second clear optical aperture at a
location at which the strength of the electric field is
substantially reduced, to prevent sputtering of the optical window
(which creates aluminum-containing contamination), and to prevent
deposition onto the optical window.
[0010] Embodiments of the present invention may include a window
for protecting an access region for access to a process chamber
from an electric field generated adjacent to the process chamber
window. The window may be a window member configured with outer and
chamber sides and an annular groove extending from the outer side
into the member parallel to the axis. The annular groove defines a
first section of the access region to be protected from the
electric field, and the window member is further configured with a
clear optical aperture having an annular wall configured with a
length between the outer side and the chamber side. The clear
optical aperture may be partly surrounded by the annular groove and
may be further configured with a diameter. A coating of a material
such as yttrium oxide is provided on the annular wall of the clear
optical aperture. The annular wall with the coating having an inner
coating diameter that is substantially the same as a value of the
length of the clear optical aperture in the window member.
[0011] An other embodiment of the present invention may include a
multi-function process chamber window assembly for protecting an
access region for access to a process chamber from an electric
field generated adjacent to the process chamber window, for
admitting at least one gas to the process chamber, and for
providing optical access to the chamber. An annular shield may have
a length extending parallel to an axis of the region and be
fabricated from material adapted to substantially block the
electric field. A window member is configured with respect to the
access region axis, the member being configured with outer and
chamber sides and an annular groove extending from the outer side
into the member. The groove defines a first section of the access
region to be protected from the electric field. The groove is
configured to receive a portion of the shield to protect the first
section of the access region from the electric field. The groove
receives the annular shield, and the shield extends out of the
groove and away from the outer side so that a second section of the
access region is defined within the annular shield. The annular
shield protects the second section from the electric field. The
window member is further configured with a first clear optical
aperture defined by a first annular wall configured with a length
between the outer side and the chamber side. The first clear
optical aperture is partly surrounded by the annular groove, and
the first clear optical aperture is further configured with a
diameter for clear optical access. A coating is provided on the
first annular wall. The first annular wall with the coating has an
inner coating diameter that is substantially the same as a value of
the axial length of the first clear optical aperture. The coating
protects the first clear optical aperture from effects of the
electric field so that the protection extends past the shield in
the annular groove to the chamber side of the window member.
[0012] Yet an other embodiment of the present invention may include
a multi-function process chamber window assembly for protecting an
access region for access to a process chamber from an electric
field generated adjacent to the process chamber window while
providing at least two gas inlets to the process chamber and
allowing optical access to the chamber. The assembly may include an
integrated shield and gas supply unit for protecting the access
region from the electric field. The unit may be configured with a
thin annular protrusion at a first end and with an annular body
that is thicker than the protrusion. The body may be further
configured to extend to a second end. The body may be further
configured with a first annular wall defining a unit clear optical
aperture extending from the first end to the second end. A further
body configuration may provide a first gas supply bore extending
and intersecting the unit clear optical aperture adjacent to the
first end. The body may be further configured with a first coupler
and the unit fabricated from material adapted to substantially
block the electric field so that the unit clear optical aperture is
protected from the electric field. A window member of the assembly
may be configured with outer and chamber sides and a groove
extending from the outer side into the member. The groove is
configured to receive the thin annular protrusion to protect a
first section of the access region from the electric field. The
member may be further configured with a second coupler configured
to cooperate with the first coupler to hold the protrusion in the
groove with the unit extending away from the outer side of the
member so that a second section of the access region is defined by
and is protected by the body from the electric field. The window
member may be further configured with a window member clear optical
aperture having a second annular wall configured with a length
between the outer side and the chamber side. The window member
clear optical aperture is partly surrounded by the thin annular
protrusion received in the annular groove. The window member clear
optical aperture may be further configured with a diameter. A
coating is provided on the second annular wall. The second annular
wall with the coating has an inner coating diameter that is
substantially the same as a value of the axial length of the window
member clear optical aperture. The coating protects the window
member clear optical aperture from the electric field.
[0013] It will be obvious, however, to one skilled in the art, that
embodiments of the present invention may be practiced without some
or all of these specific details. In other instances, well known
process operations have not been described in detail in order not
to obscure the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The embodiments of the present invention will be readily
understood by reference to the following detailed description in
conjunction with the accompanying drawings in which like reference
numerals designate like structural elements, and wherein:
[0015] FIG. 1 is a schematic view of an embodiment of an apparatus
of the present invention for protecting an access region into a
process chamber from an electric field;
[0016] FIG. 2A is a side cross-sectional view of an embodiment of a
window of the present invention for protecting an access region
into the process chamber from the electric field generated adjacent
to the window;
[0017] FIG. 2B is a plan view of the window embodiment shown in
FIG. 2A, illustrating a groove for a shield, a gas bore and a first
clear optical aperture;
[0018] FIG. 2C is a side cross-sectional view of another embodiment
of the window of the present invention, illustrating a projection
on the window;
[0019] FIG. 3A is a side cross-sectional view of the window
embodiment of FIG. 2B assembled with a shield and with an
embodiment of a fitting separate from the shield;
[0020] FIG. 3B is a cross-sectional view taken along line 3B-3B in
FIG. 3A, illustrating the assembled fitting of FIG. 3A configured
with seals;
[0021] FIG. 3C is a cross-sectional view taken along line 3C-3C in
FIG. 3A, illustrating the assembled fitting of FIG. 3A configured
with an embodiment of an optical window;
[0022] FIG. 3D is a three-dimensional view of the fitting of FIG.
3A, showing a port for access to the embodiment of the optical
window;
[0023] FIG. 4A is a side cross-sectional view of the assembled
shield and embodiment of the fitting separate from the shield,
illustrating another embodiment of the optical window;
[0024] FIG. 4B is a cross-sectional view taken along line 4B-4B in
FIG. 4A, showing the FIG. 4A embodiment of the optical window;
[0025] FIG. 4C is a cross-sectional view taken along line 4C-4C in
FIG. 4A, showing the FIG. 4A embodiment of the fitting with a gas
inlet to gas bores of the fitting;
[0026] FIG. 5A is a side cross-sectional view showing the chamber
window embodiment of FIG. 2A assembled with a shield and
multi-function fitting integral with the shield, with one
embodiment of an optical window near the chamber window; and
[0027] FIG. 5B is a side cross-sectional view of the shield and
multi-function fitting integral with the shield of FIG. 5A,
illustrating the assembled fitting of FIG. 5A configured with the
FIG. 4A embodiment of the optical window.
[0028] Other aspects and advantages of embodiments of the invention
will become apparent from the following detailed description, taken
in conjunction with the accompanying drawings, illustrating by way
of example the principles of embodiments of the present
invention.
DETAILED DESCRIPTION
[0029] Embodiments of an invention are described for apparatus, and
for a multi-function process chamber window assembly, for
protecting an access region for access to a process chamber from an
electric field generated adjacent to a window of the chamber. The
protecting may be by shielding access openings in the window from
electrical fields, wherein the openings allow multiple types of
access to semiconductor manufacturing chambers. For an opening that
is a gas bore for injecting process gas into the chamber, the
protection is from the electric field. For an opening that is a
clear optical aperture providing optical access into the chamber,
the protection is also from effects of the electric field, and this
protection may extend past a shield so that an entire length of the
clear optical aperture is protected.
[0030] In one embodiment of the present invention, a window member
is configured with respect to an access region axis, the member
being configured with an annular groove extending into the member
parallel to the axis. The annular groove may be configured to
define a first section of the access region to be protected from
the electric field. The window member may be further configured
with a clear optical aperture having an annular wall extending
co-axially with the axis and configured with an axial length
between the outer side and the chamber side. The clear optical
aperture may be partly surrounded by the annular groove and may be
further configured with a diameter. An Yttrium oxide coating may be
provided on the annular wall of the clear optical aperture. The
annular wall with the coating may have an inner coating diameter
that is substantially the same as a value of the axial length of
the clear optical aperture.
[0031] In another embodiment of the present invention, a
multi-function process chamber window assembly is provided for
protecting an access region for access to a process chamber. The
protection is from an electric field generated adjacent to the
process chamber window. The window assembly may admit at least one
gas to the process chamber and may provide optical access to the
chamber. An annular shield having a length extending parallel to an
axis region axis may be fabricated from material adapted to
substantially block the electric field. A window member may be
configured with respect to the access region axis. The member may
also be configured with an annular groove extending parallel to the
axis to define a first section of the access region to be protected
from the electric field. The groove may be configured to receive a
portion of the shield to protect the first section of the access
region from the electric field. When the groove receives the
annular shield, the shield may extend out of the groove so that a
second section of the access region is defined within the annular
shield. The annular shield may be configured to protect the second
section from the electric field. The window member may be further
configured with a first clear optical aperture defined by a first
annular wall extending co-axially with the axis and configured with
an axial length between the outer side and the chamber side. The
first clear optical aperture may be partly surrounded by the
annular groove and may be further configured with a diameter for
clear optical access. An exemplary Yttrium oxide coating on the
first annular wall may have an inner coating diameter that is
substantially the same as a value of the axial length of the first
clear optical aperture. The exemplary Yttrium oxide coating
protects the first clear optical aperture from effects of the
electric field so that the protection extends past the shield in
the annular groove to the chamber side of the window member.
[0032] FIG. 1 shows a schematic view of an apparatus 40 of the
present invention for protecting an access region for access to a
process chamber. The protection may be from an electric field
generated adjacent to a window of the chamber. The access region
may allow access to a semiconductor manufacturing process chamber,
for example. The electric field is applied to the process chamber
adjacent to the access region for exemplary gas injectors and
process analysis and measurement tools. FIG. 1 shows the apparatus
40 including a vacuum processing chamber 42 having a substrate
holder 44 providing a suitable clamping force to a substrate 46.
The top of the chamber 42 may be provided with a dielectric window
48. One of many access openings, or ports, 50 is shown
schematically as being provided in the window 48 to permit access
to the interior of the chamber 42.
[0033] FIG. 2A is an enlarged cross-sectional view showing the
window 48 as a process chamber window with exemplary ports 50, and
showing spaced vertical dot-dot-dash lines defining an exemplary
cylindrical access region 52. The access region may thus be a
three-dimensional volume within an exemplary hollow cylinder
defined by the lines. In the embodiment of the access region 52
shown in FIG. 2A, the access region 52 extends into the window 48,
as described below. The portion of the access region extending into
the window 48 may be referred to as a first section (see bracket
52-1). The access region is also shown extending above the window
48, and the portion of the access region 52 above the window 48 may
be referred to as a second section (see bracket 52-2). For other
embodiments of the access region 52, similar lines may also define
another three-dimensional shape, for example, and the other
embodiment of the access region 52 would also be defined by such
other three-dimensional shape.
[0034] FIG. 1 also schematically shows the chamber 42 provided with
facilities 54 that require access to the chamber 48 via the access
region 52. For example, the facilities 54 may provide access to the
chamber 42 for process analysis or measurement as described below,
which may be referred to as optical access. The facilities 54 may
also provide access to the chamber 42 to facilitate conducting
deposition or etching processes in the chamber 42, such as by
supplying process gases to the chamber 42. As one example of the
facilities 54, process gas may be supplied from a gas supply
through the access region 52 into the chamber 42. With a pump (not
shown) reducing the pressure in the chamber 42 for the deposition
or etching processes, a source 58 of RF energy with an impedance
matching circuit is connected to a coil 60 (see also FIG. 2A) to
energize the gas in the chamber and maintain a high density (e.g.,
10.sup.-11 to 10.sup.-12 ions/cm.sup.3) plasma in the chamber 42.
The coil 60 may be the type that inductively couples RF energy into
the chamber 42 through the window 48 to provide the high density
plasma for conducting the deposition or etching processes in the
chamber 42. During that coupling, the coil 60 generates an electric
field (see exemplary lines 62, FIG. 2A).
[0035] FIG. 2A shows that without the use of embodiments of a
shield of the present invention, the electric field 62 may extend
between turns of the coil 60 above the top of the window 48 and may
extend in the window 48 through the ports 50. This generation of
the electric field 62 without the use of the shield embodiments of
the present invention tends to induce an undesired plasma in the
ports 50 within the access region 52. For example, the tendency may
be to induce the undesired plasma may be induced in a bore through
which the gas is supplied, or in a clear optical aperture through
which optical access is provided, as described below. The undesired
induced plasma may result in undesired deposition of particles on
various parts within the process chamber 42, including on the
substrate, which lowers process yield.
[0036] The embodiments of the present invention may be used to
substantially avoid the problems caused by such undesired plasma
induced in the access region 52, while providing other advantages
described below. For example, in the enlarged cross-sectional view
of FIG. 2A, the window 48 is shown as a multi-function process
chamber window with exemplary ports 50. In the FIG. 2A embodiment,
the process chamber window 48 is shown in relation to the access
region 52 and to sections 52-1 and 52-2. A longitudinal axis X of
the window 48 is identified for reference. The window 48 may also
be described as a window member, and is shown configured with a
groove 64, for example. The groove 64 extends in the window
parallel to the axis X to a depth defined by an axial end. FIG. 2B
shows that the groove 64 may be configured with an annular shape
that that extends circularly around the axis X. The groove 64 is
thus configured to surround the access region.
[0037] In the use of the embodiment of the window 48 shown in FIG.
2A, the groove 64 may receive a shield 66 (e.g., FIG. 3A) for
protecting the access region 52. The protection is from the
electric field 62 that is generated as described above. The field
62 is shown in FIG. 2A without the shield embodiment of the present
invention, the field 62 extending adjacent to the window 48 in that
the field 62 extends above the window, for example. One embodiment
of the shield is identified as 66-1 in FIGS. 3A, 3B, and 4A.
Another embodiment of the shield is identified as 66-2 in FIGS. 5A
and 5B. References to the shield 66 apply to each embodiment. The
shield 66 may be fabricated from material adapted to substantially
block the electric field 62 from entering the access region 52.
Such material and other configuration of the shield 66 provides an
electric field-free condition within the shield (i.e., within the
access region 52). For the desired protection, the shield 66 may be
configured as a three-dimensional structure, such as a cylindrical
shield member 68 that has a shape that conforms to that of the
access region 52, and the shield 66 is connected to an electrical
ground. FIG. 3A shows that with respect to embodiment 66-1, one end
of the shield member 68 of the shield 66 is received in the groove
64 to encompass section 52-1 of the access region. Also, the shield
member 68 is shown configured to extend in the direction of the X
axis out of the groove 64. By reference to FIG. 2B it may be
understood that when the shield member 68 is received in the groove
64, the shield member 68 encompasses the access region 52. Also,
the location of the bracket 52-2 in FIG. 2C indicates that the
shield member 68 encompasses the axial length of the section 52-2
of the access region.
[0038] Referring to FIG. 2A, the window 48 is shown further
configured with an outer side 70 that is outside of the chamber 42,
and with a chamber side 72 that is inside the chamber. The groove
64 extends into the window 48 through the outer side. FIGS. 2A and
2B show the window configured with a plenum 74 that may distribute
process gas to the chamber via a plurality of nozzles 76. The
plenum is configured with an annular shape having a diameter less
than that of the groove 64. The plenum extends to a depth about
half way between the outer side 70 and the chamber side 72. FIG. 2B
shows (in dashed lines) an exemplary eight of the nozzles 76, which
intersect (and thus are connected to) the plenum and extend to the
chamber side 72, which is shown as a flat surface parallel to the
outer side 70. FIG. 2A shows that a portion of the plenum 74 is
encompassed by the groove 64, and is thus in the access region 52.
According to the particular process to be conducted in the chamber
42, the window 48 may be made from quartz or ceramic, for example.
In the embodiment described herein, the window may be made from
ceramic, such as aluminum oxide, which has desired characteristics
of tensile strength, thermal conductivity, and chemical resistance.
The window may also be made from aluminum nitride, which has
desired characteristics of tensile strength and thermal
conductivity.
[0039] FIGS. 2A and 2B also show the window 48 further configured
with a clear optical aperture 78 that may be identified as a first
(or window) clear optical aperture to distinguish from other clear
optical apertures described below. The first clear optical aperture
78 is configured with an annular wall 80 extending co-axially with
the axis X and configured with an axial length L (FIG. 2A) between
side 70 and side 72. The first clear optical aperture 78 is partly
surrounded by the annular groove 64, and may further be configured
with a diameter D1. The diameter D1 may be selected to provide
desired access to the chamber, such as optical access by which an
observation device (not shown) may view into the chamber for
spectroscopy, for example. This may include infrared spectroscopy,
for example. Also, plasma properties such as ion flux, e.g., may be
measured, or the composition of deposits in the chamber may be
determined. For use in the above-described spectroscopic
observation, for example, the diameter D1 must be generally not
less than about one-half inch. This diameter D1 may correspond to
the above-described minimum diameter of the clear optical aperture,
that is the minimum diameter that is required to enable proper
access to the optical data that originates in the process chamber.
The first clear optical aperture 78 may also be used to introduce
process gas into the chamber 48. The process gas introduced by the
first clear optical aperture 78 may be different from the gas
supplied by the plenum 74, for example, and may vary according to
the type of processing to be done in the chamber.
[0040] FIGS. 2A and 2B also show the annular wall 80 provided with
a layer, such as a coating, 82. The coating 82 has an inner coating
diameter that is substantially the same as a value of the axial
length L of the clear optical aperture 78. The coating 82 may be of
a type that does not readily combine with chamber gases, and
especially not with fluorine. For example, the clear optical
aperture 78 is open to the chamber, thus the plasma that is
generated in the chamber 42 may enter the clear optical aperture
78. Even though the shield 66 and other shield embodiments
(described below) are configured to substantially reduce the
strength of the electric field 62 that may extend across the clear
optical aperture 78, the reduced-strength electric field may cross
clear optical aperture 78 and may interact with the plasma. Without
the coating 82, an aluminum-containing ceramic such as aluminum
oxide or aluminum nitride, could react with fluorine, for example,
to form aluminum fluoride, which will form particles easily removed
from the wall 80 during processing inside the chamber, such as by
flaking off, which particles would enter the chamber 48.
Embodiments of the clear optical aperture 78 having the coating 82
of the type that does not readily combine with chamber gases
include coating materials having higher chemical resistance, e.g.,
to fluorine, than the chemical resistance of the underlying ceramic
material. Thus, relatively few of the exemplary aluminum fluoride
particles are formed and enter the chamber 48, such that process
yield may increase.
[0041] Exemplary materials for the coatings 82 that are of the type
that do not readily combine with chamber gases, include: yttrium
oxide; yttrium oxide with pores sealed with methacylate ester or
sealed with another polymer such as PTFE; or cerium oxide; or
zirconium oxide; or yttria-stabilized zirconia; or
thermally-sprayed aluminum oxide. To sputter a coating 82 of, for
example, yttrium oxide requires ion bombardment of high energy, for
example, and with the higher chemical resistance, such coating 82
on the first clear optical aperture 78 results in the low rate of
aluminum fluoride formation.
[0042] An unexpected aspect of the chamber window 48 relates to the
above-described minimum diameter of the clear optical aperture.
There is an inverse relationship between the value of such diameter
D1 and the ability of the window 48 of a minimum thickness to
withstand forces at high vacuum. Also, to meet the requirements of
the above-described optical access, diameter D1 must not be less
than the minimum diameter of the clear optical aperture. Thus the
thickness of the window 48 may be the minimum required for adequate
strength when the diameter D1 has a value of the minimum diameter
of the clear optical aperture. With this in mind, the exemplary 0.5
inch minimum diameter D1 of the clear optical aperture is also a
value of an acceptable thickness L of the window 48, and is also an
acceptable diameter for the application of the coating 82 to the
entire surface of the wall 80. For example, a torch plasma process
may be performed in Argon using an yttrium oxide powder. The torch
process generates blobs of powder that splat on the surface to be
coated. Ideally, the torch plasma process is directed at an angle
of ninety-degrees to the surface to be coated. Because the clear
optical aperture 78 has the cylindrical wall 80, the ninety-degree
direction is not possible. A limitation of the process is to not
direct the process at less than 45 degrees. With a 0.5 inch
diameter D1 configuration of the optical aperture 78 of the window
48, and at the 45 degree direction, the torch plasma process is
effective to direct the coating of yttrium oxide 0.25 inches into
the cylinder defined by the wall 80 and have proper adhesion of the
coating. As a result, by directing the coating of yttrium oxide
0.25 inches into each end of the cylinder defined by the wall 80,
the entire 0.5 inch length L of the cylinder defined by the wall 80
may be provided with the coating 82, and at the same time the
diameter requirements of the clear optical apertures for the
exemplary spectroscopy, and the window strength requirements, are
met.
[0043] FIG. 2C shows another embodiment of the window, or window
member, 48 in which the chamber side 72 of the window member may be
configured with a projection 90 defined by an axially-extending
surface 92 and a flat surface 94 parallel to the chamber side. The
nozzles 76 intersect the axially-extending surface 92 and provide
improved distribution of the gas into the chamber 48.
[0044] FIG. 3A shows a further configuration of the plenum 74 for
assisting in alignment of the window 48 during assembly with an
embodiment 100-1 of a multi-function fitting 100. The window member
48 with the shield 66 and the fitting 100 combine to define an
assembly. The plenum 74 is configured with a first pin hole, or pin
bore, 102 centered on the axis of the annular plenum. The first pin
bore has a diameter larger than the width of the plenum 74 and
defines a location for alignment with the fitting 100. The fitting
is configured with a body 101 provided with a gas bore, or conduit,
104 that is configured to supply process gas to the plenum 74. The
body 101 is further configured with a second pin hole, or pin bore,
106 coaxial with the gas bore 104, and having a diameter larger
than the diameter of the gas bore 104. The diameter of the bore 106
may be equal to the diameter of the first pin bore 102. In assembly
of the window 48 with the fitting 100, an alignment pin 108 may be
inserted into the second pin hole 106, and the first pin hole 102
aligned with the pin 108 to properly locate the fitting 100
relative to the window 48.
[0045] In the above description of FIG. 3A, the embodiment 66-1 of
the shield 66 was said to be received in the groove 64 to encompass
section 52-1 of the access region. The shield member 68 was said to
be shown extending in the direction of the X axis out of the groove
64 to encompass the axial length of the section 52-2 of the access
region (as shown by the length of the bracket 52-2 in FIG. 3A).
With this in mind, it may be understood that the outer surface 70
outside of the shield 66-1 may be provided with an annular-shaped
thin flat shield 109 to block components of the electric field 62
that are parallel to the axis X. The flat shield 109 may be
fabricated from the same material as the shield 66, for example.
The flat shield 109 is thus mounted under the coil 60 on the outer
side 70 of the window 48 and extends outwardly from the shield
66-1. With the flat shield 109 mounted and with the pin 108 used to
properly locate the fitting 100 relative to the window 48, the
shield 66-1 may also be located and secured relative to the window
48. FIG. 3A shows the shield 66-1 with the cylindrical shield
member 68 shaped to conform to that of the access region 52. FIG.
3A also shows the shield 66-1 received in the groove 64
encompassing section 52-1 of the access region, and extending in
the direction of the X axis out of the groove 64 to encompass the
access region 52, including the axial length of section 52-2 of the
access region. The shield 66-1 is configured with a lower mount
flange, or first coupling, 110 cooperating with the flat shield 109
and with a fastener to secure the shield member 86 on the flat
shield that is on the window member 48. For ease of illustration,
the lower mount flange 110 is shown in FIG. 3A only once, it being
understood that the flange 110 may be provided at three, for
example, locations around the bottom of the shield 66-1.
[0046] FIG. 4A shows a top of the shield 66-1 adjacent to a top of
the fitting 100-1. The shield 66-1 is there shown configured with
an upper mount flange, or second coupling, 112 cooperating with a
fitting mount 114 and a fastener to secure the shield member 86 to
the fitting 100-1. The respective coupling 112 and mount 114 are
pulled together by the fastener so that the fitting is pressed
downwardly onto the window member 48, as is described in more
detail below. For ease of illustration, the flange 112 is shown in
FIG. 4A only once, it being understood that the flange 112 may be
provided at three, for example, locations around the top of the
shield 66-1. As mounted and secured, the shields 66-1 and 109 are
in position to protect the access region 52 from the electric field
62. Also as mounted and secured, the fitting 100-1 is in position
to admit at least one gas to the window member 48 for injection
into the process chamber 42, and to provide optical access through
the first clear optical aperture 78 to the chamber. The fitting
100-1 is thus a multi-function fitting received within the second
section 52-2 of the access region 52 defined by the shield 66-1 for
protection from the electric field.
[0047] FIG. 3A shows one embodiment 100-1 of the fitting in which
the body 101 is configured with a second clear optical aperture 116
having a second annular wall 117 extending co-axially with the axis
X and vertically aligned with the coated first clear optical
aperture 78. The second clear optical aperture 116 serves both to
supply gas to the first clear optical aperture 78 and to allow
clear optical access to the chamber 42 through the first clear
optical aperture 78, e.g., as described above with respect to the
exemplary spectroscope (not shown) mounted above the chamber 42 out
of the electric field. To facilitate this gas supply, the fitting
body 101 is further configured with a gas supply bore, or conduit,
118 initially extending parallel to the axis X and then angles to
intersect the second clear optical aperture as described below.
[0048] It may be understood that the chamber 42 is operated at a
vacuum, such as in a range of 5-400 milliTorr. To maintain the
vacuum, the fitting 100-1 is sealed to the window member 48 by a
first seal structure 120 that may include seals 122 and 124. In a
general sense, the seal structure 120 is between the fitting 100-1
and the window member 48. The seal structure 120 is configured so
that in response to the upper and lower couplers 110, 112, and 114
urging the fitting 100-1 toward the window member 48, the seal
structure 120 provides an air-tight seal of the fitting 100-1 to
the window member 48. Thus, gas flows from the gas supply bore 104
into the annular plenum 74 separately from the respective first and
second clear optical apertures 78 and 116. Also, gas flows from the
second clear optical aperture 116 into the first clear optical
aperture 78 separately from the gas supply bore 104 and from the
annular plenum 74. Also, unwanted gases (e.g., atmospheric) do not
flow into the chamber.
[0049] The seal structure 120 is configured to be mounted in a
lower, or window, end 126 of the fitting 100. The end 126 is
configured with two spaced annular recesses 128, spaced radially
outward from the second clear optical aperture 116. The seals 122
and 124 may be configured with a seal member, such as an O-ring or
pad, 130 that may be mounted in each recess 128 and squeezed by the
fitting 100-1 that is urged toward the window member 48.
[0050] FIG. 3A also shows the lower end 126 configured with one
embodiment 132-1 of an optical window assembly 132, and FIG. 4A
shows an upper, or second, end 134 of the fitting 100-1 configured
with another embodiment 132-2 of the optical window assembly. FIG.
3A shows the optical window assembly 132-1 configured with a seat
136 adjacent to the first seal structure 120 and co-axial with the
access region axis X. The seat 136 is configured with a recess 138
to receive a second seal, such as an O-ring, 140. The assembly
132-1 further includes an optical window 142 received in (mounted
on) the seat 136. With respect to the optical data that is received
from the chamber 42, the optical window 142 may have an optical
characteristic of transmitting that optical data out of the second
clear optical aperture and into a suitable optical unit, such as a
collimator (not shown) for further transmission to the exemplary
spectrometer (not shown). For ease of illustration, FIGS. 3A and 3C
show the portion of the window 142 to the right of the axis X, it
being understood that the window 142 is disk-like (circular). The
second seal 140 between the seat 136 and the optical window 142
prevents gas from leaking into and past the second clear optical
aperture 116 into the first clear optical aperture 78, while
allowing optical access through the second clear optical aperture
116 and through the first clear optical aperture 78 into the
chamber 42. A clamp 144 may be used to hold the window 142 against
the second seal 140 and the seat 136. To provide access to the
optical window 142, FIGS. 3A and 3D show that the wall 117 of the
fitting 100-1 is further configured with at least one access port
150. The port 150 is an opening in the body 101 and is located on a
side of the optical window 142 that is away from the window member
48. As may be necessary for such access to the window 142 or the
clamp 144, many ports 150 may be provided in the wall 117.
[0051] By reference to FIG. 4A it may be understood that in one
embodiment of the fitting 100-1 with the embodiment 132-2 of the
optical window assembly 132, the second clear optical aperture 116
is configured so that the second annular wall 117 is clear, e.g.,
unobstructed and open, from the low end 126 (that is adjacent to
the window member 48) to the upper end 134 (spaced from the window
member). For the other embodiment 132-2 of the optical window
assembly 132, the second end 134 of the fitting 100 is further
configured with a third sealing seat 152. The structure of the
assembly 132-2 is similar to that of the assembly 132-1, and
includes the seat 152 configured with a recess 154 to receive a
second seal, such as an O-ring, 156. FIGS. 4A and 4B show the
assembly 132-2 further configured with an optical window 158
received in (mounted on) the seat 152. The second seal 156 between
the seat 152 and the optical window 158 prevents gas from leaking
into and past the second clear optical aperture 116 into the first
clear optical aperture 78, while allowing optical access through
the second clear optical aperture 116 and through the first clear
optical aperture 78 into the chamber 42. A clamp 160 may be used to
hold the window 158 against the second seal 156 and the seat
152.
[0052] Because the second clear optical aperture 116 is open from
the low end 126 to the upper end 134 of the fitting 100, plasma
from the chamber 48 may flow through the first clear optical
aperture 78 and into the second clear optical aperture 116. As
described above concerning the first clear optical aperture 78,
even though the shield 66-1, the shield 109, and other shield
embodiments (described below) are configured to substantially
reduce the strength of the electric field 62 that may extend across
the fitting and the second clear optical aperture 116, the electric
field 62 of some small strength may cross second clear optical
aperture 116 and interact with the plasma. To protect the wall 117
from the effects of such low strength electric field 62, FIG. 4A
also shows the annular wall 117 provided with protective layers,
such as second coatings 162. Each of the coatings 162 has an inner
coating diameter that is substantially the same as a value of the
coating diameter D1 of the first clear optical aperture 78. The
coatings 162 may be the same type as coating 82, and may be
deposited on the wall 177, all as described above. Thus, about
one-half inch at each end 134 and 126 of the wall 117 may be
provided with the coatings 162. As noted above, without the
coatings 162 an exemplary aluminum-containing ceramic will react
with fluorine to form aluminum fluoride, which will form particles
easily removed from the wall 80 during processing inside the
chamber, such as by flaking off, which particles would enter the
chamber 48. In the embodiment of the second clear optical aperture
116 having the coatings 162, e.g., of yttrium oxide that requires
ion bombardment of high energy to be sputtered, in the second clear
optical aperture 116 there is a low rate of aluminum fluoride
formation adjacent to the coatings 162, which may have a combined
one inch of the wall 117 protected from the effects of the low
strength electric field 62 in the above exemplary configuration
with D1 of 0.5 inch. In other words, one coating 162 may be a
second Yttrium oxide coating on the second annular wall 117, and
the second coating may extend from the first end 126 for a distance
about equal to the diameter of the second annular wall 117. Also,
the other coating may be a third Yttrium oxide coating on the
second annular wall 117, and the second coating may extend from the
second end 134 for a distance about equal to the diameter of the
second annular wall 117.
[0053] FIGS. 3A and 4A show the fitting body 101-1 further
configured with the second gas supply bore 118 extending parallel
to the axis X, radially outward from the axis X and from the second
clear optical aperture 116, but radially inward of the first bore
104. FIG. 3A shows the bore 118 configured with an angle section
directed toward and intersecting the second clear optical aperture
116. The angle section avoids interference by the bore 118 with the
first seal structure 120, for example. The second bore 118 may also
be a single bore sized to supply process gas to the second clear
optical aperture 116 and then to the first clear optical aperture
78 for distribution into the chamber 48.
[0054] For the embodiment of the optical window assembly 132-1
configured with the seat 136 adjacent to the first seal structure
120, the window 142 and the bores 104 and 118 are configured to
avoid interference with each other. In this case, the bores 104 and
118 are oriented in the body 101 radially outside of the window
142, i.e., away from the axis X enough to extend vertically in the
body 101-1 past and not intersect the window 142. Also, prior to
assembly of the fitting 100-1 with the window member 48, the lower
end 126 of the wall 117 of the fitting 101-1 may be provided with
the coating 162, which may be the second coating 162 described
above. The axial length of such second coating 162 may extend from
the end 162 to the location of the seat 136.
[0055] Further, consistent with the above-described minimum length
from the window 48 to the optical window 142 (as necessary to avoid
the noted contamination and damage to the optical window 142), the
optical window 142 may be at an axial location between the ends 126
and 134. That axial location may be selected according to the
process to be performed in the chamber 42, for example, which may
include the strength of the electric field 62. It may be understood
that the process, for example, may be such as to make it necessary
to locate the optical window 142 at a location at which the
strength of the electric field is substantially reduced, to prevent
sputtering of the optical window (which creates aluminum-containing
contamination), and to prevent deposition onto the optical window.
In that event, the embodiment 100-1 of the fitting may be provided
with the embodiment 132-2 of the optical window, i.e., the optical
window 158 as shown in FIG. 4A. Further, in the implementation of
the embodiment 132-2 the fitting 100-1 may have an axial length
from end 126 to end 134 of from about three to about six inches,
and the shield 66-1 may have a corresponding axial length 52-2
above the window 48, for example. The optical window 158 may thus
be located spaced from the window 48, where the strength of the
electric field 62 is substantially reduced, so that there are
minimal amounts of the above-described contamination and damage to
the optical window 158. The end 134 with the optical window 158 is
thus spaced from the first end 126 to locate the seat 154 (and thus
the optical window 158) where the strength of the electric field is
substantially reduced as compared to the electric field strength
adjacent to the process chamber window 48. This optical window
location may thus provide the above-described minimum length from
the window 48 to the optical window 158.
[0056] FIG. 4A shows a gas inlet 180 that for the two bores 104 and
118, for example, is a dual gas inlet. The inlet 180 may be secured
(as by suitable fasteners) to the fitting to align inlet bores with
horizontal extensions of the bores 104 and 118. For embodiments of
the present invention with a requirement for more than two gases,
the inlet 180 may be configured with more inlet bores and the
fitting configured with more bores of the type of bores 104 or 118,
for example.
[0057] FIGS. 5A and 5B illustrate another embodiment 100-2 of the
fitting 100 assembled to the window 48 shown in FIG. 2A. The
fitting 100-2 is configured with the fitting functions and the
functions of the shield 66 integral, or integrated into one piece,
so that the fitting may be referred to as an integrated shield and
gas supply unit, identified by reference number 100-2. Reference
numbers used above that refer to similar structure are used below
to describe the unit 100-2, and a "-2" is used to refer to
structure unique to the unit 100-2. The integral shield aspects
(similar to shield 66) are referred to as 66-2. The body 101-2 of
the unit 100-2 is configured with the shield 66-2. The shield 66-2
is configured with a thin annular shield protrusion 190 at the
first (lower) end 126. The groove 64 of the window 48 may receive
the shield protrusion 190 for protecting the access region 52, and
the protection is that described above in re FIG. 2A.
[0058] The unit 101-2 may be fabricated from material adapted to
substantially block the electric field 62 from entering the access
region 52. Such material, and other configuration of the unit 101-2
(i.e., the protrusion 190) promote an electric field-free condition
within the unit. For the desired protection, above the protrusion
190 the unit 100-2 is configured as a solid cylinder member 68-2
configured to be received in the access region 52 and to provide
the gas supply and optical access described above. FIG. 5A shows
that with respect to embodiment 66-2, the protrusion 190 is
received in the groove 64 to encompass section 52-1 of the access
region. Also, the unit 100-2 is shown configured to extend in the
direction of the X axis out of the groove 64 to encompass the axial
section 52-2 (FIG. 2C) of the access region.
[0059] For clarity of illustration, FIG. 5A does not show the
configuration shown in FIG. 3A of the plenum 74 and window 48 for
assisting in alignment of the window 48 during assembly with
embodiments of a multi-function fitting 100. However, in the manner
shown in FIG. 3A, the unit 100-2 and window 48 may be configured
with the first pin hole 102, and with the body 101 provided with
the gas bore 104 configured to supply process gas to the plenum 74,
with the second pin hole 106, and the alignment pin 108 to properly
locate the fitting 100 relative to the window 48. The embodiment
66-2 of the shield 66 is thus received in the groove 64 to
encompass section 52-1 of the access region, and the body 101 of
the unit 100-2 extends in the direction of the X axis out of the
groove 64 to encompass the axial section 52-2 of the access region.
The pin 108 may be used to properly locate the fitting 100 relative
to the window 48, and the shield 66-2 (via the protrusion 190) may
also be located and placed in the groove 64. FIG. 5A shows the
shield 66-2 with the protrusion 190 around the section 52-1 of the
access region 52. FIG. 5A also shows that with the shield 66-2
received in the groove 64 encompassing section 52-1 of the access
region, the body 101-2 extends in the direction of the X axis
encompass the axial section 52-2 (FIG. 2A) of the access region.
The body 101-2 is configured with a lower mount flange 200
configured to cooperate with the flat shield 109 and a fastener to
secure the body 101-2 to the window member 48. The flange 200 and
window 48 are pulled together by the fastener so that the fitting
is pressed downwardly onto the window member 48 so that the vacuum
is maintained by the same first seal structure 120, as described
above.
[0060] As mounted and secured, the integral shield 66-2 is also in
position to protect the access region 52 from the electric field
62. Also as mounted and secured, the unit 100-2 is in position to
admit at least one gas to the window member 48 for injection into
the process chamber 42, and to provide optical access through the
first clear optical aperture 78 to the chamber. The unit 100-2 is
thus also a multi-function fitting and shield received within the
second section 52-2 of the access region 52 for protection from the
electric field.
[0061] FIG. 5A shows an embodiment of the unit 100-2 in which the
body 101-2 is configured with the second clear optical aperture 116
that may be the same as that used in FIG. 3A. The body 101-2 is
further configured with the gas supply bore 104 extending parallel
to the axis X and vertically aligned with the annular plenum 74,
and with the bore 118 to supply gas to the second clear optical
aperture 116. FIG. 5A shows the lower end 126 also configured with
one embodiment 132-1 of the optical window assembly 132, as
described above. FIG. 5B shows the body 101-2 configured so that
the upper end 134 of the body 101-2 is configured with the other
embodiment 132-2 of the optical window assembly 132, also as
described above. Thus, the embodiment 100-1 of the fitting may be
provided with the embodiment 132-2 of the optical window, i.e., the
optical window 158 as shown in FIG. 4A. In the implementation of
the embodiment 132-2 the fitting 100-1 may have an axial length
from end 126 to end 134 as described above so that the optical
window 158 is located where the strength of the electric field 62
is substantially reduced, which may result in minimal amounts of
the above-described contamination and less damage to the optical
window 158. Such optical window location may be from about three
inches to about six inches from the window 48, for example. It may
be understood that the second clear optical aperture 116 is thus
configured so that the second annular wall 117 is clear, e.g.,
unobstructed and open, from the low end 126 (that is adjacent to
the window member 48) to the upper end 134 (spaced from the window
member), and is also provided with the coatings 162.
[0062] FIG. 5B shows the gas inlet 180 for the two bores 104 and
118, for example, to provide a dual gas inlet. The inlet 180 may be
secured (as by suitable fasteners) to the fitting to align inlet
bores with horizontal extensions of the bores 104 and 118. For
embodiments of the present invention with a requirement for more
than two gases, the inlet 180 may be configured with more inlet
bores and the fitting with more bores of the type of bores 104 or
118, for example.
[0063] In review, embodiments of the present invention satisfy the
described needs by providing further improvements in accessing
processing chamber 42, where multiple access is provided by the
window member 48 with the clear optical aperture 78 and with the
dual supply gas bores 104 (feeding plenum 74) and 118 (for gas
supply to aperture 78). This need is met, for example, by
overcoming the conflicting requirements for the relatively large
minimum diameter of the clear optical aperture 78 for the optical
function and for a relatively small diameter of one or more gas
bores 104 or 118 (or of the plenum 74) for gas supply to the
chamber 42 to avoid plasma formation, for example. The conflicting
requirements are overcome by the combination of protection of the
dual gas supply bores 104 and 118 (and plenum 74) and the first
clear optical aperture 78, protection being from the electric field
62 established by the coil 60 that surrounds the clear optical
aperture 78. In the embodiments, the shield 66 is configured to
extend into the window 48 to provide such protection for the first
section 52-1 of the clear optical aperture 78. The remaining second
section 52-2 of the clear optical aperture 78 may be provided with
the protective coating 82 to provide such protection from the
reduced-strength electric field 62.
[0064] The protective coating 82 (such as yttrium oxide) provided
on the annular wall 80 of the clear optical aperture 78 is
facilitated by the inner coating diameter D1 substantially the same
as the value of the axial length L of the clear optical aperture.
Because the exemplary 0.5 inch minimum diameter D1 of the clear
optical aperture 78 is also a value of an acceptable thickness L of
the window 48, and because both the diameter D1 and length L are
also acceptable for applying the coating 82 to the entire surface
of the wall 80 (e.g., by the torch plasma process), the thickness
of the window 48 may be reduced to the value of L, the requirements
of the minimum diameter of the clear optical aperture 78 may be
met, and the dual shielding and coating protection of the first
clear optical aperture 78 is facilitated.
[0065] In addition, for providing optical access for exemplary
spectroscopic observation of chamber processes, embodiments of the
present invention described with respect to FIGS. 4A and 5B enable
location of the optical window 158 where the strength of the
electric field 62 is substantially reduced, which may result in
minimal amounts of the above-described contamination and less
damage to the optical window 158, and allow provision of the
minimum diameter of the clear optical aperture 78 of the exemplary
one-half inch.
[0066] Further, for situations (e.g., process) that permit the
optical window 142 (FIGS. 3A and 5A) to be located nearer to the
end 126, this location is within both embodiments 66-1 and 66-2 of
the shield 66, such that the optical window 142 is protected by
these shields 66 and the wall 117 is protected by the coating 162
(shown in FIGS. 4A and 5B) as described above.
[0067] Although the foregoing invention has been described in some
detail for purposes of clarity of understanding, it will be
apparent that certain changes and modifications may be practiced
within the scope of the appended claims. For example and not
limitation, while the shield 66 has been described as being
cylindrical, the shield 66 may be configured with other
three-dimensional shapes. Exemplary shield cross-sectional
configurations include square and oval.
[0068] Accordingly, the present embodiments 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 within the
scope and equivalents of the appended claims.
* * * * *