U.S. patent application number 10/933605 was filed with the patent office on 2005-02-03 for apparatus and method for depositing materials onto microelectronic workpieces.
Invention is credited to Carpenter, Craig M., Dando, Ross S., Derderian, Garo J., Mardian, Allen P., Tschepen, Kimberly R..
Application Number | 20050022739 10/933605 |
Document ID | / |
Family ID | 30000012 |
Filed Date | 2005-02-03 |
United States Patent
Application |
20050022739 |
Kind Code |
A1 |
Carpenter, Craig M. ; et
al. |
February 3, 2005 |
Apparatus and method for depositing materials onto microelectronic
workpieces
Abstract
Reactors for vapor deposition of materials onto a
microelectronic workpiece, systems that include such reactors, and
methods for depositing materials onto microelectronic workpieces.
In one embodiment, a reactor for vapor deposition of a material
comprises a reaction chamber and a gas distributor. The reaction
chamber can include an inlet and an outlet. The gas distributor is
positioned in the reaction chamber. The gas distributor has a
compartment coupled to the inlet to receive a gas flow and a
distributor plate including a first surface facing the compartment,
a second surface facing the reaction chamber, and a plurality of
passageways. The passageways extend through the distributor plate
from the first surface to the second surface. Additionally, at
least one of the passageways has at least a partially occluded flow
path through the plate. For example, the occluded passageway can be
canted at an oblique angle relative to the first surface of the
distributor plate so that gas flowing through the canted passageway
changes direction as it passes through the distributor plate.
Inventors: |
Carpenter, Craig M.; (Boise,
ID) ; Mardian, Allen P.; (Boise, IID) ; Dando,
Ross S.; (Nampa, ID) ; Tschepen, Kimberly R.;
(Boise, ID) ; Derderian, Garo J.; (Boise,
ID) |
Correspondence
Address: |
PERKINS COIE LLP
PATENT-SEA
P.O. BOX 1247
SEATTLE
WA
98111-1247
US
|
Family ID: |
30000012 |
Appl. No.: |
10/933605 |
Filed: |
September 2, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10933605 |
Sep 2, 2004 |
|
|
|
10191889 |
Jul 8, 2002 |
|
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|
6821347 |
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Current U.S.
Class: |
118/715 ;
427/248.1 |
Current CPC
Class: |
C23C 16/45544 20130101;
C23C 16/45565 20130101 |
Class at
Publication: |
118/715 ;
427/248.1 |
International
Class: |
C23C 016/00 |
Claims
1-62. (Canceled)
63. A method for forming a thin layer on a micro-device workpiece,
comprising: providing a flow of gas to a gas distributor having a
distributor plate with an inner region and an outer region; passing
a first portion of the gas flow through the inner region of the
plate along a path extending at an oblique angle relative to a
plane defined by the plate such that the first portion of the gas
exits the plate having a first flow characteristic; and flowing a
second portion of the gas flow through the outer region of the
plate such that the second portion of the gas exits the plate
having a second flow characteristic different than the first flow
characteristic.
64. The method of claim 63 wherein flowing the second portion of
the gas through the outer region of the plate comprises dispensing
the second portion of the gas at an angle that is at least
substantially normal to the plane defined by the plate.
65. The method of claim 63 wherein passing the first portion of the
gas through the inner region of the plate comprises dispensing the
first portion of the gas at an angle that is oblique relative to
the plane defined by the plate.
66. The method of claim 63 wherein: flowing the second portion of
the gas through the outer region of the plate comprises dispensing
the second portion of the gas at an angle that is at least
substantially normal to the plane defined by the plate; and passing
the first portion of the gas through the inner region of the plate
comprises dispensing the first portion of the gas at an angle that
is oblique relative to the plane defined by the plate.
67. The method of claim 63 wherein flowing the second portion of
the gas through the outer region of the plate comprises dispensing
the second portion of the gas at an angle that is oblique relative
to the plane defined by the plate.
68. The method of claim 63 wherein passing the first portion of the
gas through the inner region of the plate comprises dispensing the
first portion of the gas at an angle of approximately 15.degree. to
approximately 85.degree. relative to the plane defined by the
plate.
69. The method of claim 63 wherein: flowing the second portion of
the gas through the outer region of the plate comprises dispensing
the second portion of the gas at an oblique angle .alpha. relative
to the plane defined by the plate; and passing the first portion of
the gas through the inner region of the plate comprises dispensing
the first portion of the gas at an oblique angle .beta. relative to
the plane defined by the plate different than the angle
.alpha..
70. The method of claim 63 wherein: flowing the second portion of
the gas through the outer region of the plate comprises dispensing
the second portion of the gas at an oblique angle .alpha. relative
to the plane defined by the plate; and passing the first portion of
the gas through the inner region of the plate comprises dispensing
the first portion of the gas at the oblique angle .alpha. relative
to the plane defined by the plate.
71. The method of claim 63, further comprising directing a portion
of the gas flow through a gap between a peripheral portion of the
distributor plate and a sidewall.
72. A method for forming a thin layer on a micro-device workpiece,
comprising: providing a flow of gas to a gas distributor having a
distributor plate with an inner region and an outer region;
restricting a portion of the gas flow from passing through a
plurality of first passageways at the inner region of the
distributor plate; passing another portion of the gas flow through
a plurality of second passageways at the outer region of the
distributor plate; and flowing still another portion of the gas
flow through a gap around a peripheral edge of the distributor
plate.
Description
TECHNICAL FIELD
[0001] The present invention is related to the field of thin film
deposition in the manufacturing of micro-devices.
BACKGROUND
[0002] Thin film deposition techniques are widely used in the
manufacturing of microelectronic devices to form a coating on a
workpiece that closely conforms to the surface topography. The size
of the individual components in the devices is constantly
decreasing, and the number of layers in the devices is increasing.
As a result, the density of components and the aspect ratios of
depressions (e.g., the ratio of the depth to the size of the
opening) is increasing. The size of workpieces is also increasing
to provide more real estate for forming more dies (i.e., chips) on
a single workpiece. Many fabricators, for example, are
transitioning from 200 mm to 300 mm workpieces, and even larger
workpieces will likely be used in the future. Thin film deposition
techniques accordingly strive to produce highly uniform conformal
layers that cover the sidewalls, bottoms and corners in deep
depressions that have very small openings.
[0003] One widely used thin film deposition technique is Chemical
Vapor Deposition (CVD). In a CVD system, one or more precursors
that are capable of reacting to form a solid thin film are mixed in
a gas or vapor state, and then the precursor mixture is presented
to the surface of the workpiece. The surface of the workpiece
catalyzes the reaction between the precursors to form a thin solid
film at the workpiece surface. The most common way to catalyze the
reaction at the surface of the workpiece is to heat the workpiece
to a temperature that causes the reaction.
[0004] Although CVD techniques are useful in many applications,
they also have several drawbacks. For example, if the precursors
are not highly reactive, then a high workpiece temperature is
needed to achieve a reasonable deposition rate. Such high
temperatures are not typically desirable because heating the
workpiece can be detrimental to the structures and other materials
that are already formed on the workpiece. Implanted or doped
materials, for example, migrate in the silicon substrate when a
workpiece is heated. On the other hand, if more reactive precursors
are used so that the workpiece temperature can be lower, then
reactions may occur prematurely in the gas phase before reaching
the substrate. This is not desirable because the film quality and
uniformity may suffer, and also because it limits the types of
precursors that can be used. Thus, CVD techniques may not be
appropriate for many thin film applications.
[0005] Atomic Layer Deposition (ALD) is another thin film
deposition technique that addresses several of the drawbacks
associated with CVD techniques. FIGS. 1A and 1B schematically
illustrate the basic operation of ALD processes. Referring to FIG.
1A, a layer of gas molecules A.sub.x coats the surface of a
workpiece W. The layer of A.sub.x molecules is formed by exposing
the workpiece W to a precursor gas containing A.sub.x molecules,
and then purging the chamber with a purge gas to remove excess
A.sub.x molecules. This process can form a monolayer of A.sub.x
molecules on the surface of the workpiece W because the A.sub.x
molecules at the surface are held in place during the purge cycle
by physical adsorption forces at moderate temperatures or
chemisorption forces at higher temperatures. The layer of A.sub.x
molecules is then exposed to another precursor gas containing
B.sub.y molecules. The A.sub.x molecules react with the B.sub.y
molecules to form an extremely thin solid layer of material on the
workpiece W. The chamber is then purged again with a purge gas to
remove excess B.sub.y molecules.
[0006] FIG. 2 illustrates the stages of one cycle for forming a
thin solid layer using ALD techniques. A typical cycle includes (a)
exposing the workpiece to the first precursor A.sub.x, (b) purging
excess A.sub.x molecules, (c) exposing the workpiece to the second
precursor B.sub.y, and then (d) purging excess B.sub.y molecules.
In actual processing several cycles are repeated to build a thin
film on a workpiece having the desired thickness. For example, each
cycle may form a layer having a thickness of approximately 0.5-1.0
.ANG., and thus it takes approximately 60-120 cycles to form a
solid layer having a thickness of approximately 60 .ANG..
[0007] FIG. 3 schematically illustrates an ALD reactor 10 having a
chamber 20 coupled to a gas supply 30 and a vacuum 40. The reactor
10 also includes a heater 50 that supports the workpiece W and a
gas dispenser 60 in the chamber 20. The gas dispenser 60 includes a
plenum 62 operatively coupled to the gas supply 30 and a
distributor plate 70 having a plurality of holes 72. In operation,
the heater 50 heats the workpiece W to a desired temperature, and
the gas supply 30 selectively injects the first precursor A.sub.x,
the purge gas, and the second precursor B.sub.y as shown above in
FIG. 2. The vacuum 40 maintains a negative pressure in the chamber
to draw the gases from the gas dispenser 60 across the workpiece W
and then through an outlet of the chamber 20.
[0008] One drawback of ALD processing is that it is difficult to
avoid mixing between the first and second precursors in the chamber
apart from the surface of the workpiece. For example, a precursor
may remain on surfaces of the gas dispenser or on other surfaces of
the chamber even after a purge cycle. This results in the unwanted
deposition of the solid material on components of the reaction
chamber. The first and second precursors may also mix together in a
supply line or other area of a reaction chamber to prematurely form
solid particles before reaching the surface of the workpiece. Thus,
the components of the ALD reactor and the timing of the
A.sub.x/purge/B.sub.y/purge pulses of a cycle should not entrap or
otherwise cause mixing of the precursors in a manner that produces
unwanted deposits or premature reactions.
[0009] Another drawback of ALD processing is that the film
thickness may be different at the center of the workpiece than at
the periphery. To overcome this problem, the center of some
distributor plates do not have any holes 72. In practice, however,
this may cause the film at the center of the workpiece to be
thinner than the film at the periphery. Moreover, the center
portion of such plates may become coated with the solid material
because it is difficult to purge all of the precursors from this
portion of the gas dispenser 60 during normal purge cycles.
Therefore, there is a need to resolve the problem of having a
different film thickness at the center of the workpiece than at the
periphery.
SUMMARY
[0010] The present invention is directed toward reactors for
deposition of materials onto a micro-device workpiece, systems that
include such reactors, and methods for depositing materials onto
micro-device workpieces. In one embodiment, a reactor for
depositing a material comprises a reaction chamber and a gas
distributor that directs gas flows to a workpiece. The reaction
chamber can include an inlet and an outlet, and the gas distributor
is positioned in the reaction chamber. The gas distributor has a
compartment coupled to the inlet to receive a gas flow and a
distributor plate including a first surface facing the compartment,
a second surface facing the reaction chamber, and a plurality of
passageways. The passageways extend through the distributor plate
from the first surface to the second surface. Additionally, at
least one of the passageways has at least a partially occluded flow
path through the plate. For example, the occluded passageway can be
canted at an oblique angle relative to the first surface of the
distributor plate so that gas flowing through the canted passageway
changes direction as it passes through the distributor plate.
[0011] The compartment of the gas distributor can be defined by a
sidewall, and the distributor plate can extend transverse relative
to the sidewall. In one embodiment, the distributor plate has an
inner region, an outer region, and a peripheral edge spaced
laterally inward from the sidewall to define a gap between the
peripheral edge and the sidewall. In other embodiments, the
peripheral edge of the distributor plate can be coupled to the
sidewall.
[0012] The distributor plate can have several different
embodiments. The distributor plate, for example, can have a first
plurality of passageways in the inner region that are canted at an
oblique angle relative to the first surface of the distributor
plate, and a second plurality of passageways in the outer region
that are generally normal to the first surface of the distributor
plate. In another embodiment, all of the passageways through the
distributor plate can be canted at an angle. The size of the
passageways can also vary across the distributor plate. In one
embodiment, a first plurality of passageways in the inner region
have a cross-sectional dimension of approximately 0.01-0.07 inch,
and a second plurality of passageways in the outer region have a
cross-sectional dimension of approximately 0.08-0.20 inch. In still
other embodiments, a first plurality of passageways in the inner
region are canted at a first oblique angle relative to the first
surface of the distributor plate, and a second plurality of
passageways in the outer region are canted at a second oblique
angle relative to the first surface of the distributor plate. The
canted passageways are generally angled downward and radially
outward from the first surface to the second surface to direct the
gas flow radially outward across the surface of the workpiece. For
example, the canted passageways can extend at an angle of
approximately 15 degrees to approximately 85 degrees relative to
the first surface of the distributor plate. The passageways,
however, can be angled at different angles or canted in different
directions in other embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIGS. 1A and 1B are schematic cross-sectional views of
stages in atomic layer deposition processing in accordance with the
prior art.
[0014] FIG. 2 is a graph illustrating a cycle for forming a layer
using atomic layer deposition in accordance with the prior art.
[0015] FIG. 3 is a schematic representation of a system including a
reactor for vapor deposition of a material onto a microelectronic
workpiece in accordance with the prior art.
[0016] FIG. 4 is a schematic representation of a system having a
reactor for depositing a material onto a micro-device workpiece in
accordance with one embodiment of the invention.
[0017] FIG. 5 is an isometric, cross-sectional view illustrating a
portion of a reactor for depositing a material onto a micro-device
workpiece in accordance with an embodiment of the invention.
[0018] FIG. 6 is a cross-sectional view of a reactor for depositing
a material onto a micro-device workpiece in accordance with another
embodiment of the invention.
[0019] FIG. 7 is a partial cross-sectional view of a distributor
plate for use in a reactor for depositing a material onto a
micro-device workpiece in accordance with another embodiment of the
invention.
[0020] FIG. 8 is a schematic representation of a system including a
reactor for depositing a material onto a micro-device workpiece in
accordance with another embodiment of the invention.
DETAILED DESCRIPTION
[0021] The following disclosure is directed toward reactors for
depositing a material onto a micro-device workpiece, systems
including such reactors, and methods for depositing a material onto
a micro-device workpiece. Many specific details of the invention
are described below with reference to depositing materials onto
micro-device workpieces. The term "micro-device workpiece" is used
throughout to include substrates upon which and/or in which
microelectronic devices, micromechanical devices, data storage
elements, and other features are fabricated. For example,
micro-device workpieces can be semiconductor wafers, glass
substrates, insulative substrates, and many other types of
materials. The term "gas" is used throughout to include any form of
matter that has no fixed shape and will conform in volume to the
space available, which specifically includes vapors (i.e., a gas
having a temperature less than the critical temperature so that it
may be liquified or solidified by compression at a constant
temperature). Additionally, several aspects of the invention are
described with respect to Atomic Layer Deposition ("ALD"), but
certain aspects may be applicable to other types of deposition
processes. Several embodiments in accordance with the invention are
set forth in FIGS. 4-8 and the related text to provide a thorough
understanding of particular embodiments of the invention. A person
skilled in the art will understand, however, that the invention may
have additional embodiments, or that the invention may be practiced
without several of the details in the embodiments shown in FIGS.
4-8.
[0022] A. Deposition Systems
[0023] FIG. 4 is a schematic representation of a system 100 for
depositing a material onto a micro-device workpiece W in accordance
with an embodiment of the invention. In this embodiment, the system
100 includes a reactor 110 having a reaction chamber 120 coupled to
a gas supply 130 and a vacuum 140. For example, the reaction
chamber 120 can have an inlet 122 coupled to the gas supply 130 and
an outlet 124 coupled to the vacuum 140.
[0024] The gas supply 130 includes a plurality of gas sources 132
(identified individually as 132a-c), a valve assembly 133 having a
plurality of valves 134 (identified individually as 134a-c), and a
plurality of gas lines 136 and 137. The gas sources 132 can include
a first gas source 132a for providing a first precursor gas "A," a
second gas source 132b for providing a second precursor gas "B,"
and a third gas source 132c for providing a purge gas P. The first
and second precursors A and B can be the constituents that react to
form the thin, solid layer on the workpiece W. The p-urge gas P can
a type of gas that is compatible with the reaction chamber 120 and
the workpiece W. The first gas source 132a is coupled to a first
valve 134a, the second gas source 132b is coupled to a second valve
134b, and the third gas source 132c is coupled to a third valve
134c. The valves 134a-c are operated by a controller 142 that
generates signals for pulsing the individual gases through the
reaction chamber 120 in a number of cycles. Each cycle can include
a first pulse of the first precursor A, a second pulse of the purge
gas, a third pulse of the second precursor B, and a fourth pulse of
the purge gas.
[0025] The reactor 110 in the embodiment illustrated in FIG. 4 also
includes a workpiece support 150 and a gas distributor 160 in the
reaction chamber 120. The workpiece support 150 can be a plate
having a heating element to heat the workpiece W to a desired
temperature for catalyzing the reaction between the first precursor
A and the second precursor B at the surface of the workpiece W. The
workpiece support 150, however, may not be heated in all
applications.
[0026] The gas distributor 160 is positioned at the inlet 122 of
the reaction chamber 120. The gas distributor 160 has a compartment
or plenum 162 that is defined, at least in part, by a sidewall 164.
The compartment or plenum 162 can be further defined by a chamber
lid 166. The gas distributor 160 further includes a distributor
plate 170 having a first surface 171a facing the compartment 162, a
second surface 171b facing away from the compartment 162, and a
plurality of passageways 172 (identified by reference numbers 172a
and 172b). As explained in more detail below, a gas flow F in the
compartment 162 flows through the passageways 172a-b and through a
gap 180 between the sidewall 164 and the distributor plate 170. As
explained in more detail below, this particular embodiment of the
distributor plate 170 performs the following functions: (a) directs
the gas flow F to provide a more uniform film thickness across the
workpiece W; and (b) limits areas in the reaction chamber where the
precursors can adduct and mix prematurely before contacting the
workpiece.
[0027] B. Gas Distributors and Distributor Plates
[0028] FIG. 5 illustrates a particular embodiment of the gas
distributor 160 and the distributor plate 170 in greater detail. In
this embodiment, the distributor plate 170 has an inner region 173a
with a first plurality of passageways 172a and an outer region 173b
with a second plurality of passageways 172b. The first passageways
172a extend from the first surface 171a to the second surface 171b,
and at least a portion of each of the first passageways 172a is at
least partially occluded along a flow path to the plate 170. In
this particular embodiment, the first passageways 172a are occluded
by being canted at an oblique angle relative to the first surface
171a and/or the plane defined by the plate 170. The term
"occluded," as used herein, is not limited to an obstruction that
blocks the passageways 172, but rather means that some of the gas
molecules flowing through the first passageways 172a cannot flow
through the plate 170 along a direct "line-of-sight" between the
first surface 171a and the second surface 171b normal to the plane
defined by the plate 170. It will be appreciated that canting the
first passageways 172a at an oblique angle relative to the plate
170 can either fully or at least partially block the direct
line-of-sight to the workpiece while still allowing gas to flow
through the first passageways 172a. The first passageways 172a can
be canted at an angle of approximately 15.degree. to approximately
85.degree. relative to the plane defined by the plate 170. The
second passageways 172b extend through the plate 170 generally
normal to the first surface 171a such that they provide a direct
line-of-sight to the workpiece throughout the full cross-sectional
dimension of the second passageways 172b. The second passageways
172b can also have bevels 176 at the first surface 171a and/or the
second surface 171b.
[0029] The distributor plate 170 is carried by a number of
retainers 177 that are coupled to the lid 166 or another component
of the reaction chamber 120. The retainers 177 are brackets, posts,
or other suitable devices that can hold the distributor plate 170
relative to the inlet 122 and the sidewall 164. In this embodiment,
the distributor plate 170 has a peripheral edge 175 spaced apart
from the sidewall 164 by an annular gap 180. In operation,
therefore, the gas flow F has a first component F.sub.1 that flows
through the first passageways 172a, a second component F.sub.2 that
flows through the second passageways 172b, and a third component
F.sub.3 that flows through the gap 180. The first passageways 172a
direct the first flow component F.sub.1 downward and radially
outward to prevent over-saturating the center portion of the
workpiece with the precursors. The second passageways 172b direct
the second flow component F.sub.2 downward and generally normal to
the plate 170 to provide more gas molecules to an outer region of
the workpiece. The gap 180 also provides an enhanced flow of gas at
the outer and peripheral regions of the workpiece.
[0030] Several embodiments of the distributor plate 170 are
accordingly expected to provide more uniform saturation of the
workpiece W with the first and second precursors A and B to provide
a more uniform layer of material on the workpiece. Additionally,
because the inner region 173a of the plate 170 includes the first
plurality of passageways 172a, the surface areas upon which the
first and second precursors A and B can adduct is reduced compared
to conventional plates that do not have any openings in the inner
region. This is expected to reduce the build up of the deposited
material on the first surface 171a of the distributor plate 170. It
is also expected that such a reduction in the surface area will
enhance the ability to control the uniformity of the deposited
layer and the endpoints of the gas pulses for better quality
depositions and enhanced throughput.
[0031] The first passageways 172a can also have a different
cross-sectional dimension than the second passageways 172b as shown
in the particular embodiment illustrated in FIG. 5. The first
passageways, for example, can have openings of approximately
0.01-0.07 inch, and the second passageways 172b can have openings
of approximately 0.08-0.20 inch. In a particular embodiment, the
first passageways 172a at the inner region 173a have a circular
opening with a diameter of approximately 0.03 inch, and the second
passageways 172b in the outer region 173b have a circular opening
with a diameter of approximately 0.10 inch. It will be appreciated
that the cross-sectional size of the first and second passageways
172a-b can be the same, or that they can have cross-sectional
dimensions that are different than the ranges set forth above.
[0032] The passageways 172 can accordingly be configured to further
enhance or restrict the gas flow to particular areas of the
workpiece by canting, or otherwise occluding selected passageways,
and/or varying the sizes of the cross-sectional dimensions of the
passageways. In the embodiment shown in FIG. 5, for example, the
smaller cross-sectional dimension of the first passageways 172a
inhibits gas molecules from contacting the central region of the
workpiece W, and the larger cross-sectional dimension of the second
passageways 172b enhances the number of gas molecules that contact
the outer region of the workpiece. Therefore, the cross-sectional
dimensions and the angles of inclination of the passageways can be
used either separately or together to provide the desired
distribution of gas to the surface of the workpiece.
[0033] FIG. 6 is a cross-sectional view of a distributor plate 670
in accordance with another embodiment of the invention. Several
components of the distributor plate 670 are the same as the
distributor plate 170, and thus like reference numbers refer to
like components in FIGS. 4-6. The distributor plate 670 can include
a plurality of passageways 172 that are canted at an oblique angle
relative to the plane defined by the plate 670. In this embodiment,
all of the passageways 172 are canted at the same angle. The angle
of inclination can be approximately 15 degrees to approximately 85
degrees. In operation, the embodiment of the distributor plate 670
shown in FIG. 6 has a first flow component F.sub.1 that flows
radially outwardly and downward from the plate 670, and a second
flow component F.sub.2 that flows through the gap 180. The
passageways 172 can have the same cross-sectional dimensions, or
they can have different cross-sectional dimensions similar to the
plate 170 described above.
[0034] FIG. 7 is a partial cross-sectional view of a distributor
plate 770 in accordance with another embodiment of the invention.
The distributor plate 770 is similar to the distributor plate 170,
and thus like reference numbers refer to like components in FIGS.
4, 5 and 7. In this embodiment, the first passageways 172a at the
inner region 173a are canted at a first angle .alpha., and the
second passageways 172b in the second region 173b are canted at a
second angle .beta.. The angle .alpha. is generally less than the
angle 62 relative to the plane P-P defined by the plate 770. As
such, the first passageways 172a have a first occlusion area
A.sub.1 in which there is no direct line-of-sight through the plate
770 to the workpiece W along a path normal to the plate 170. The
second passageways 172b, however, have a smaller occlusion area
A.sub.2 because the higher angle .beta. allows gas to pass
completely through a portion of the second passageways 172b along a
path normal to the plate 770 or the workpiece W. By increasing the
size of the occlusion area A, for the first passageways 172a
relative to the occlusion area A.sub.2 for the second passageways
172b, fewer gas molecules are likely to be deposited on the central
region C of the workpiece W. It will be appreciated that the
distributor plate 770 can have variable canting of the passageways
172 from the center to the perimeter of the plate along a continuum
or throughout several regions in which the angle of incline
increases toward the periphery of the plate 770. Accordingly, in
other embodiments, the distributor plate 770 can have more than two
regions in which the passageways are canted at different
angles.
[0035] C. Additional Deposition Systems
[0036] FIG. 8 is a schematic illustration of another embodiment of
a system 800 for depositing a material onto a microelectronic
workpiece. The system 800 is similar to the system 100, and thus
like reference numbers refer to like components in FIGS. 4 and 8.
The difference between the system 800 and the system 100 is that
the system 800 includes a gas distributor 860 with a distributor
plate 870 that extends to the sidewall 164 to eliminate the gap 180
shown in FIG. 4. It will be appreciated that the distributor plate
870 can include any of the distributor plates explained above with
reference to FIGS. 4-7. Therefore, other aspects of the invention
include a completely enclosed compartment or plenum 862.
[0037] From the foregoing, it will be appreciated that specific
embodiments of the invention have been described herein for
purposes of illustration, but that various modifications may be
made without deviating from the spirit and scope of the invention.
Accordingly, the invention is not limited except as by the appended
claims.
* * * * *