U.S. patent application number 09/732341 was filed with the patent office on 2001-10-18 for apparatus and method for selectively restricting process fluid flow in semiconductor processing.
Invention is credited to Rose, David Jay.
Application Number | 20010031560 09/732341 |
Document ID | / |
Family ID | 26868075 |
Filed Date | 2001-10-18 |
United States Patent
Application |
20010031560 |
Kind Code |
A1 |
Rose, David Jay |
October 18, 2001 |
Apparatus and method for selectively restricting process fluid flow
in semiconductor processing
Abstract
A semiconductor processing apparatus (10) is disclosed which
includes a process chamber (12) and at least one substrate support
(18) disposed within the process chamber (12) operable to support a
substrate wafer (20). The semiconductor processing apparatus
includes at least one showerhead assembly (14) disposed within the
process chamber (12) facing the substrate support (18) and has a
showerhead plate (16). The showerhead plate (16) has a plurality of
passageways (17) extending therethrough for directing process fluid
toward a substrate wafer (20) disposed on the substrate support
(18). A blocking assembly (21) is disposed within the process
chamber (12), the blocking assembly has an active position (32)
between the showerhead assembly (14) and the substrate support (18)
to restrict the flow of process fluid between the showerhead
assembly (14) and the substrate support (18). The blocking assembly
also has a neutral position (30) that does not restrict the flow of
process fluid between the showerhead assembly (14) and the
substrate support (18).
Inventors: |
Rose, David Jay; (Dallas,
TX) |
Correspondence
Address: |
Jacqueline J. Garner
Texas Instruments Incorporated
M/S 3999
P. O. Box 655474
Dallas
TX
75265
US
|
Family ID: |
26868075 |
Appl. No.: |
09/732341 |
Filed: |
December 7, 2000 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60172428 |
Dec 17, 1999 |
|
|
|
Current U.S.
Class: |
438/706 ;
438/716; 438/745; 438/782 |
Current CPC
Class: |
H01L 21/6708 20130101;
H01L 21/6715 20130101 |
Class at
Publication: |
438/706 ;
438/716; 438/745; 438/782 |
International
Class: |
H01L 021/302; H01L
021/461 |
Claims
What is claimed is:
1. A semiconductor processing apparatus comprising: a process
chamber; at least one substrate support disposed within the process
chamber operable to support a substrate wafer; at least one
showerhead assembly disposed within the process chamber facing the
substrate support, the showerhead assembly having a showerhead
plate; the showerhead plate having a plurality of passageways
extending therethrough for directing a process fluid toward a
substrate wafer disposed on the substrate support; and a blocking
assembly disposed within the process chamber, the blocking assembly
having an active position between the showerhead assembly and the
substrate support to restrict process fluid flow from the
showerhead and a neutral position which allows unrestricted process
flow.
2. The apparatus of claim 1 wherein the blocking assembly further
comprises a rotator associated with the blocking assembly such that
the rotator is secured within the process chamber, the rotator
operable to selectively position the blocking assembly in its
active position and its neutral position.
3. The apparatus of claim 1 wherein the blocking assembly further
comprises: a rod assembly extending from the process chamber; an
arm assembly coupled to the rod assembly and extending
substantially perpendicular from the rod assembly, at least one
blocking disk coupled to the arm assembly; and a rod assembly
having a selectively variable length such that the rod assembly
operates to selectively raise or lower the blocking disk relative
to the showerhead assembly.
4. The apparatus of claim 1 further comprising: the process chamber
having a top portion; and the blocking assembly depending from the
top portion.
5. The apparatus of claim 1 further comprising: the process chamber
having a bottom portion; and the blocking assembly extending from
the bottom portion.
6. The apparatus of claim 1 further comprising at least one
blocking disk releasably coupled to the blocking assembly.
7. The apparatus of claim 1 further comprising: a plurality of
substrate supports; a plurality of showerhead assemblies disposed
within the process chamber facing the respective substrate
supports; and a plurality of blocking assemblies for selectively
restricting process fluid flow from the showerhead assemblies.
8. The apparatus of claim 1 wherein the blocking assembly further
comprises at least one blocking disk having a heating element
disposed within the blocking disk.
9. The apparatus of claim 1 wherein the blocking assembly further
comprises: at least one blocking disk having an outer diameter
smaller than the outer diameter of the substrate wafer; and the at
least one blocking disk selectively movable between the active
position and the neutral position.
10. A process fluid blocking assembly for controlling the flow of a
process fluid in a semiconductor processing apparatus comprising: a
rotator selectively rotatable; at least one blocking disk having a
substantially circular configuration; a linkage having a first end
and a second end; and the first end coupled to the rotator and the
second end coupled to the at least one blocking disk such that the
blocking disk rotates as the rotator rotates.
11. The process fluid blocking assembly of claim 10 further
comprising: the linkage further having a plurality of ends operable
to support a plurality of blocking disks; and a plurality of
blocking disks attached to the plurality of ends.
12. The process fluid blocking assembly of claim 10 further
comprising the rotator operable to selectively position the at
least one blocking disk within a semiconductor processing
apparatus.
13. The process fluid blocking assembly of claim 10 further
comprising: a plurality of blocking disks having multiple disk
sizes; and the plurality of blocking disks operable to releasably
couple to the linkage.
14. The process fluid blocking assembly of claim 10 further
comprising: the at least one blocking disk having a heating element
disposed within the blocking disk; and the heating element
electrically connected to a power source.
15. The process fluid blocking assembly of claim 10 further
comprising: the at least one blocking disk having an electrode
disposed therein; and the electrode electrically connected to a
power source.
16. A method for fabricating a semiconductor device on a substrate
wafer disposed in a semiconductor fabrication apparatus comprising:
supplying process fluid to a showerhead assembly positioned
opposite the substrate wafer; and selectively positioning a
blocking assembly between the showerhead assembly and the substrate
wafer to restrict the flow of process fluid from the showerhead to
the substrate wafer, thereby affecting the fabrication of the
semiconductor device.
17. The method of claim 16 further comprising moving the blocking
assembly to a position restricting the flow of process fluid
between the showerhead assembly and the substrate wafer.
18. The method of claim 16 further comprising selectively varying
the height of the blocking disk between the showerhead assembly and
the semiconductor assembly.
19. The method of claim 16 further comprising selectively varying
power to an electrode forming a portion of the blocking
assembly.
20. The method of claim 16 further comprising selectively varying
the power supplied to a heating element disposed within the
blocking assembly.
21. The method of claim 16 further comprising the process fluid
depositing a material on the substrate wafer.
22. The method of claim 16 further comprising the process fluid
etching a portion of the substrate wafer.
Description
TECHNICAL FIELD OF THE INVENTION
[0001] This invention relates in general to the field of electronic
devices. More specifically, this invention relates to an apparatus
and method for restricting process fluid flow during semiconductor
processing.
BACKGROUND OF THE INVENTION
[0002] Semiconductor fabrication typically includes depositing
material onto a semiconductor substrate wafer and etching material
from the substrate. Often these processes take place within a
process chamber containing one or more wafers and a deposition
apparatus referred to as a showerhead. The showerhead acts to
direct process fluid to the semiconductor substrate wafer. The
showerhead typically includes an inlet conduit connected to a
process fluid source outside of the process chamber and a
showerhead plate with a number of holes extending therethrough to
direct process fluid exiting the showerhead to the semiconductor
substrate wafer. Showerheads are also used in both material
deposition and etching processes to direct deposition and etching
fluid to the semiconductor substrate wafer.
[0003] Problematic edge effects often result from uneven deposition
and etch across the radius of a semiconductor substrate wafer.
These problems often result when the characteristics of a plasma
field or the flow of process fluid varies between the center of the
wafer and the edge of the wafer. Such nonuniform deposition and
etch often results in a semiconductor substrate wafer with
disparate electrical properties across its radius. Because of this
disparity portions of the wafer are often not usable for their
intended function. In the case of circular wafers, inadequate
deposition and etching of material adjacent to the outer edge of
the wafer often renders devices formed adjacent to the outer edge
of the wafer defective. As wafer diameter increases from six
inches-to eight inches-to twelve inches, the number of devices
formed adjacent to the outer edge increases significantly.
Therefore, edge defects for a twelve inch wafer result in a greater
number of unusable devices as compared with a six inch wafer.
[0004] One past solution for controlling deposition and etch across
the radius of a wafer was to alter the geometry of holes extending
through a showerhead plate. This technique allows process fluid to
be directed toward selected areas of the substrate wafer. Simply,
to increase process fluid flow to selected areas, more or larger
holes are formed in the showerhead plate opposite those areas.
However, this solution suffers from a number of drawbacks. First, a
specialized showerhead plate is typically formed for a particular
process and is often not useful for other processes. Second,
experimentation with a specialized showerhead plate is time
consuming and expensive. A complete processing run is often
required to evaluate the effectiveness of a particular geometry of
holes in a showerhead plate. This consumes valuable resources and
processing time. Third, the use of specialized showerhead plates
for each deposition and etch process step can be costly, often
requiring multiple showerhead assemblies to perform multiple
processing steps and replacing showerhead assemblies to accomplish
process changes.
SUMMARY OF THE INVENTION
[0005] Therefore, a need has arisen for an apparatus that can
selectively control deposition and etching on the outer edge of a
semiconductor substrate wafer.
[0006] A further need has arisen for an apparatus that can
selectively control the deposition and etching of material across
the radius of a semiconductor substrate wafer.
[0007] A further need has arisen for an apparatus that is operable
to selectively vary deposition and etch edge effects in a plurality
of processes.
[0008] In accordance with teachings of the present invention, an
apparatus and method are described which substantially eliminates
or reduces disadvantages and problems associated with prior
apparatuses and methods used to deposit and etch materials during
semiconductor fabrication. The apparatus includes a process chamber
and a blocking assembly disposed within the process chamber. The
blocking assembly may be selectively positioned in an active or
neutral position. When positioned in the active position, the
blocking assembly restricts process fluid flow directed toward a
substrate wafer from a showerhead assembly disposed in the process
chamber. When positioned in the neutral position the blocking
assembly does not restrict the flow of process fluid between the
showerhead assembly and the substrate wafer.
[0009] In one aspect of the present invention a semiconductor
processing apparatus is disclosed. The semiconductor processing
apparatus includes a process chamber and at least one substrate
support disposed within the process chamber operable to support a
substrate wafer. The semiconductor processing apparatus also
includes at least one showerhead assembly disposed within the
process chamber that faces the substrate support and has a
showerhead plate. The showerhead plate has a plurality of
passageways extending therethrough for directing a process fluid
toward a substrate wafer disposed on the substrate support. A
blocking assembly is disposed within the process chamber. The
blocking assembly has an active position between the showerhead
assembly and the substrate support to restrict the flow of process
fluid between the showerhead assembly and the substrate support.
The blocking assembly also has a neutral position that does not
restrict the flow of process fluid between the showerhead and the
substrate support. More specifically, the blocking assembly
includes at least one blocking disk that has an outer diameter
smaller than the outer diameter of the substrate wafer. Also, the
at least one blocking disk is selectively movable between the
active position and the neutral position.
[0010] In another aspect of the present invention a process fluid
blocking assembly for controlling the flow of a process fluid in a
semiconductor processing apparatus is disclosed. The process fluid
blocking assembly includes a rotator selectively rotatable and at
least one blocking disk having a substantially circular
configuration. The blocking assembly also includes a linkage having
a first end and a second end. The first end of the linkage is
coupled to the rotator and the second end is coupled to the at
least one blocking disk such that the blocking disk rotates as the
rotator rotates. More specifically, the process fluid blocking
assembly includes a plurality of blocking disks having multiple
disk sizes where the plurality of blocking disks is operable to
releasably couple to the linkage.
[0011] In another aspect of the present invention, a method for
fabricating a semiconductor device on a substrate wafer disposed in
a semiconductor fabrication apparatus is disclosed. The method
includes supplying process fluid to a showerhead assembly
positioned opposite the substrate wafer. The method also includes
selectively positioning a blocking assembly between the showerhead
assembly and the substrate wafer to restrict the flow of process
fluid from the showerhead to the substrate wafer. This selective
positioning of the blocking assembly affects the fabrication of the
semiconductor device.
[0012] The present invention provides a number of important
technical advantages. One technical advantage is having at least
one blocking disk that has an outer diameter smaller than the outer
diameter of the substrate wafer. This allows the deposition
apparatus to selectively control deposition on the outer edge of
the substrate wafer.
[0013] Another technical advantage of the present invention is
having a blocking assembly with an active position and a neutral
position. This allows the deposition apparatus to selectively
control the deposition and etching of material across the radius of
a substrate wafer.
[0014] Another technical advantage of the present invention is
having a plurality of blocking disks having multiple disk sizes,
operable to releasably couple to the linkage. This allows the
blocking assembly to selectively vary deposition and etch edge
effects in a plurality of processes.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] A more complete understanding of the present embodiments and
advantages thereof may be acquired by referring to the following
description taken in conjunction with the accompanying drawings, in
which like reference numbers indicate like features, and
wherein:
[0016] FIG. 1 is a schematic diagram showing a cross section of a
semiconductor processing apparatus incorporating teachings of the
present invention;
[0017] FIG. 2A is a schematic diagram showing a plan view of the
semiconductor processing apparatus of FIG. 1 with a blocking
assembly positioned in a neutral position according to teachings of
the present invention;
[0018] FIG. 2B is a schematic diagram showing a plan view of the
semiconductor processing apparatus of FIG. 1 with the blocking
assembly positioned in an active position according to teachings of
the present invention;
[0019] FIG. 3 is a schematic cross section diagram with portions
broken away of a semiconductor processing apparatus with a blocking
assembly depending from a top portion of the process chamber
according to teachings of the present invention; and
[0020] FIG. 4 is a schematic diagram of a portion of a blocking
assembly with a heating element and electrode disposed within the
blocking assembly according to teachings of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0021] Preferred embodiments and their advantages are best
understood by reference to FIGS. 1 through 4, wherein like numbers
are used to indicate like and corresponding parts.
[0022] FIG. 1 is a schematic diagram showing a cross section of a
semiconductor processing apparatus indicated generally at 10
incorporating teachings of the present invention. Semiconductor
processing apparatus 10 includes substrate supports 18 disposed
within process chamber 12 operable to support substrate wafers 20.
Semiconductor processing apparatus 10 also includes showerhead
assemblies 14. Showerhead assemblies 14 include showerhead plates
16 having a plurality of passageways 17 extending therethrough.
Process fluid conduits 15 extend through process chamber 12 and are
in fluid communication with showerhead assemblies 14 to communicate
process fluid from the exterior of process chamber 12 into
showerhead assemblies 14.
[0023] The present embodiment includes substrate supports 18,
substrate wafers 20, showerhead assemblies 14 and process fluid
conduits 15. In an alternative embodiment semiconductor processing
apparatus may include a singular substrate support 18, substrate
wafer 20 and showerhead assembly 14. Alternatively semiconductor
processing apparatus 10 may include a plurality of substrate
supports 18, substrate wafers 20 and showerhead assemblies 14.
[0024] Process fluid conduit 15 is operable to deliver process
fluids from a process fluid source (not expressly shown) which may
be externally located. Additionally, the process fluid source may
include a control system for selectively controlling the flow rate
of process fluid from the process fluid source to inlet conduit 15.
Process fluid may include any process fluid suitable to be
delivered through a showerhead assembly including process used in
deposition processes and fluids used in etch processes.
[0025] Blocking assembly 21 is disposed within process chamber 12.
Blocking assembly 21 includes rotator 22, rod assembly 24, arm
assembly 26 and blocking disks 28. Rotator 22 is secured within
process chamber 12. Rod assembly 24 is coupled to rotator 22 and
extends from process chamber 12. In the present embodiment, rod
assembly 24 extends substantially perpendicularly from process
chamber 12. Arm assembly 26 is coupled to rod assembly 24 and
extends from rod assembly 24. Blocking disks 28 are coupled to rod
assembly 26 distal to rod assembly 24.
[0026] Rotator 22 is operable to selectively rotate. Rotator 22 may
be operated mechanically or electrically. In this embodiment
rotation of rotator 22 causes rod 24 to rotate about its
longitudinal axis. In turn, rotation of rod assembly 24 causes arm
assembly 26 and the disks 28 attached thereto to rotate through a
horizontal plane through process chamber 12 such that the rotator
is operable to selectively position blocking assembly 21 in an
active position 32 (as described in FIG. 2B) and a neutral position
30 (as described in FIG. 2A).
[0027] In one embodiment rod assembly 24 may have a selectively
variable length such that the rod assembly operates to selectively
raise or lower blocking disk 28 relative to showerhead assembly 14.
Rod assembly 24 may include a telescoping configuration operated
pneumatically, mechanically, or electrically. In an alternative
embodiment, rod assembly 24 may have another configuration suitable
to selectively shorten or lengthen rod assembly 24.
[0028] Rod assembly 24 and arm assembly 26 form linkage 19. In this
embodiment linkage 19 has a T-shaped configuration. In an
alternative embodiment linkage 19 may have any suitable
configuration wherein a first end of linkage 19 is coupled to
rotator 22 and a second end of linkage 19 is coupled to blocking
disk 28. In yet another alternative embodiment linkage 19 includes
the first end coupled to rotator 22 and a plurality of ends wherein
the plurality of blocking disks 28 are coupled. In an alternative
embodiment linkage 19 may have any suitable configuration to link
blocking disk 28 to rotator 22 such that rotation of rotator 22
selectively positions blocking disk 28 in active position 32 as
described in FIG. 2B and in neutral position 30 as described in
FIG. 2A.
[0029] In the present embodiment blocking disk 28 has an outer
diameter smaller than the outer diameter of substrate wafer 20 and
has a smaller diameter than the outer diameter of shower plate 16.
In the present embodiment blocking disk 28 has a substantially
circular configuration. In an alternative embodiment, blocking disk
28 may have other configurations as desired to selectively restrict
process fluid flow from showerhead assembly 14 to substrate wafer
20.
[0030] In operation process fluid is communicated through process
fluid conduit 15 to showerhead assembly 14. Process fluid exits
showerhead assemblies 14 through passageways 17 in showerhead plate
16. Blocking assembly 21 may then be selectively positioned in
active position 32 or neutral position 30. When positioned in
neutral position 30, blocking assembly 21 does not restrict the
flow of process fluid from showerhead assembly 14 to blocking disk
28. When blocking assembly 21 is positioned in active position 32,
blocking disk 28 acts to partially restrict the flow of process
fluid exiting passageways 17 towards substrate wafer 20. Because
blocking disk 28 has an outer diameter smaller than the outer
diameter of substrate wafer 20 and because active position 32
places blocking disk 28 above the center of substrate wafer 20, the
flow of process fluid towards the center of substrate wafer 20 is
substantially restricted. The flow of process fluid to a portion of
the substrate wafer adjacent to the center portion of the substrate
wafer is substantially unrestricted. In one embodiment of the
present invention rod assembly 24 may be selectively shortened or
lengthened such that the height of blocking disks 28 relative to
substrate wafer 20 may be selectively increased or decreased. When
blocking assembly 21 is in the active position, raising or lowering
the height of blocking disk 28 relative to substrate wafer 20
affects the fabrication of the semiconductor device on substrate
wafer 20.
[0031] In yet another embodiment of the present invention blocking
disk 28 may be releasably coupled to blocking assembly 21. In
another embodiment of the present invention blocking assembly 21
includes a plurality of blocking disks 28 having multiple disk
sizes. This plurality of blocking disks 28 may be releasably
coupled to arm assembly 26.
[0032] FIG. 2A is a schematic diagram showing a plan view of the
semiconductor processing apparatus of FIG. 1 with a blocking
assembly 21 positioned in a neutral position 30 according to the
teachings of the present invention. The semiconducting processing
apparatus includes a plurality of showerhead assemblies 14 and a
blocking assembly 21 disposed within process chamber 12. Blocking
assembly 21 includes rotator 22, rod assembly 24 coupled to rotator
assembly 22, and arm assembly 26 coupled to rod assembly 24.
Blocking disks 28 are coupled to arm assembly 26 extending from rod
assembly 24.
[0033] In the present embodiment blocking assembly 21 is positioned
in neutral position 30 such that blocking disks 28 do not restrict
the flow of process fluid exiting passageways 15 and directed
towards substrate wafers 20 (as shown in FIG. 1).
[0034] FIG. 2B is a schematic diagram showing a plan view of the
semiconductor processing apparatus of FIG. 1 with the blocking
assembly 21 positioned in active position 32 according to teachings
of the present invention. When positioned in the active position 32
blocking disks 28 are positioned to restrict the flow of process
fluid exiting showerheads 14 directed towards substrate wafers 20
(as shown in FIG. 1).
[0035] FIG. 3 is a schematic diagram of a semiconductor processing
apparatus 10a with blocking assembly 21 depending from a top
portion of process chamber 12 according to teachings of the present
invention. Substrate supports 18 support substrate wafers 20
disposed within process chamber 12. Showerhead assemblies 14
including showerhead plates 16 with plurality of passageways 17
extending therethrough, are disposed in process chamber 12 facing
substrate supports 18. Process fluid inlets 15 are in fluid
communication with showerhead assemblies 14 such that process
fluids communicate through process fluid inlets 15 to showerhead
assemblies 14 and exit showerhead assemblies 14 through passageways
17. Blocking assembly 21 is disposed within process chamber 12 such
that blocking assembly depends from a top portion of process
chamber 12. Blocking assembly 21 includes rotator 22, rod assembly
24 coupled to rotator 22, and arm assembly 26 coupled to rod
assembly 24. Blocking disks 28 are coupled to arm assembly 26.
[0036] FIG. 4 is a schematic diagram of a portion of a blocking
assembly 21a with a heating element 36 and an electrode 40 disposed
within the blocking assembly according to teachings of the present
invention. The portion of blocking assembly 21a includes blocking
disk 28 coupled to arm assembly 26. Heating element 36 is disposed
within blocking disk 28a and is in electrical communication with a
heating element power supply (not expressly shown) via heating
element connection 38. Electrode 40 is disposed within blocking
disk 28a. Electrode 40 is in electrical communication with an
electrode power supply (not expressly shown) via electrode
connection 42. In an alternative embodiment, in which blocking disk
28a is releasably coupled to arm assembly 26, releasable connectors
allow for the releasable connection between heating element 36 and
heating element connection 38 and electrode 40 and electrode
connection 42.
[0037] In operation power from the heating element power supply may
be selectively delivered to heating element 36 such that heating
element 36 will selectively effect the temperature within process
chamber 12. Such heating effects include altering process fluid
flow and deposition characteristics within the chamber. Power may
also be supplied from the electrode power supply to electrode 40
via electrode connection 42 such that electrode 40 creates a plasma
field as process fluid exits showerhead assembly 14. The localized
plasma field effect from electrode 40 may selectively effect
process fluid flow and deposition characteristics within the
process chamber 12. In an alternative embodiment blocking assembly
21a may include either heating element 36 and heating element
connection 38 or electrode 40 and electrode connection 42. In
operation power may be supplied 42 to heating element 36 such that
the temperature of blocking disk 28a increases. Power may be
supplied to heating element 36 when blocking assembly 21a is either
in active position 32 (as shown in FIG. 2B) or neutral position 30
(as shown in FIG. 2A).
[0038] Power may be supplied to heating element 36 while blocking
assembly 21a is in neutral position 30 for a predetermined period
or until heating element 36 reaches a desired temperature. Blocking
assembly may then be positioned in active position 32 for
restricting the flow of process fluid exiting showerhead assembly
14. Power may continue to be supplied to heating element 36 or may
be reduced or discontinued after blocking disk 28a reaches a
predetermined temperature. In an alternative embodiment a
temperature sensor is disposed within blocking assembly 21a for
determining the temperature of blocking assembly 21a.
[0039] Power may be supplied to electrode 40 when blocking assembly
21a is either in active position 32 (as shown in FIG. 2B) or
neutral position 30 (as shown in FIG. 2A). Power may be supplied to
electrode 40 while blocking assembly 21a is in neutral position 30
and then moved into active position 32. Alternatively, power may be
initially supplied to electrode 40 when blocking assembly 40 is in
active position 30. Power may continue to be supplied to electrode
40 for an entire processing step or may be increased, decreased or
discontinued after a predetermined period.
[0040] Power may be supplied to heating element 36 and electrode 40
simultaneously. Alternatively, power may be supplied to heating
element 36 and electrode 40 independently.
[0041] Although the disclosed embodiments have been described in
detail, it should be understood that various changes, substitutions
and alterations can be made to the embodiments without departing
from their spirit and scope.
* * * * *