U.S. patent application number 11/027726 was filed with the patent office on 2005-05-26 for cvd apparatuses and methods of forming a layer over a semiconductor substrate.
Invention is credited to Campbell, Philip H., Carpenter, Craig M., Dando, Ross S., Hamer, Kevin T..
Application Number | 20050112890 11/027726 |
Document ID | / |
Family ID | 25462776 |
Filed Date | 2005-05-26 |
United States Patent
Application |
20050112890 |
Kind Code |
A1 |
Campbell, Philip H. ; et
al. |
May 26, 2005 |
CVD apparatuses and methods of forming a layer over a semiconductor
substrate
Abstract
The invention includes a method of forming a layer on a
semiconductor substrate that is provided within a reaction chamber.
The chamber has at least two inlet ports that terminate in
openings. A first material is flowed into the reaction chamber
through the opening of a first of the inlet ports. At least a
portion of the first material is deposited onto the substrate. The
reaction chamber is purged by flowing an inert material into the
reaction chamber through the opening of a second of the inlet
ports. The inert material passes from the opening and through a
distribution head that is positioned within the reaction chamber
between the first and second openings. A second material can then
be flowed into the chamber through an opening in a third inlet port
and deposited onto the substrate. The invention also includes a
chemical vapor deposition apparatus.
Inventors: |
Campbell, Philip H.;
(Meridian, ID) ; Carpenter, Craig M.; (Boise,
ID) ; Dando, Ross S.; (Nampa, ID) ; Hamer,
Kevin T.; (Meridian, ID) |
Correspondence
Address: |
WELLS ST. JOHN P.S.
601 W. FIRST AVENUE, SUITE 1300
SPOKANE
WA
99201
US
|
Family ID: |
25462776 |
Appl. No.: |
11/027726 |
Filed: |
December 30, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11027726 |
Dec 30, 2004 |
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10704316 |
Nov 6, 2003 |
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6849133 |
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10704316 |
Nov 6, 2003 |
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09932711 |
Aug 17, 2001 |
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6677250 |
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Current U.S.
Class: |
438/689 ;
257/E21.274 |
Current CPC
Class: |
C23C 16/45544 20130101;
H01L 21/31604 20130101; C23C 16/45568 20130101; C23C 16/45519
20130101 |
Class at
Publication: |
438/689 |
International
Class: |
H01L 021/302; H01L
021/461 |
Claims
1-32. (canceled)
33. A deposition apparatus comprising: a substrate platform within
a deposition chamber, the substrate platform having an upper
surface; a reaction gas inlet into the chamber having a first
opening disposed at a first distance from the upper surface of the
platform, the reaction gas inlet passing through a first chamber
surface opposing the upper surface of the platform; an inert gas
inlet passing through the first chamber surface, the inert gas
inlet having a second opening disposed at a second distance from
the: upper surface, the second distance being greater than the
first distance; and a chamber outlet passing through a second
chamber surface, the second chamber surface opposing the first
chamber surface.
34. The apparatus of claim 33 wherein the reaction gas inlet is
comprised by a valve assembly.
35. The apparatus of claim 33 further comprising a distribution
head disposed between the upper surface and the inert gas
inlet.
36. The apparatus of claim 33 wherein the distribution head is
disposed at a third distance between the first distance and the
second distance.
37. The apparatus of claim 33 wherein the outlet position opposing
the reaction gas inlet maintains directional flow of reaction gas
away from the first surface.
38. The apparatus of claim 33 wherein the reaction gas inlet is a
first reaction gas inlet and further comprising a second reaction
gas inlet into the chamber.
39. The apparatus of claim 38 wherein the second reaction gas inlet
passes through the first chamber surface.
40. The apparatus of claim 38 wherein the second reaction gas inlet
comprises a third opening disposed at a third distance from the
upper surface of the platform.
41. The apparatus of claim 40 further comprising a distribution
head disposed at a position between the third opening and the
second opening.
42. A method of depositing a layer over a substrate, the method
comprising; providing a substrate on an upper surface of a platform
disposed within a deposition chamber; introducing a reaction gas
through an inlet passing through a first chamber surface, the first
chamber surface opposing the upper surface of the platform;
directionally-flowing the reaction gas away from the first surface
toward a chamber outlet passing through a second chamber surface,
at least some of the reaction gas depositing onto the substrate
during the directional flowing.
43. The method of claim 42 wherein the second chamber surface
opposes the first chamber surface.
44. The method of claim 42 wherein the inlet is a first inlet, and
further comprising providing an inert gas into the chamber through
a second inlet.
45. The method of claim 44 wherein the second inlet passes through
the first chamber surface.
46. The method of claim 44 wherein the second inlet comprises an
opening, the method further comprising flowing the inert gas
through a dispersion head disposed between the opening and the
upper surface of the platform.
47. The method of claim 44 wherein the inert gas is provided
simultaneously with the reaction gas.
48. The method of claim 42 wherein the reaction gas is a first
reaction gas, and further comprising flowing a second reaction gas
into the chamber.
49. The method of claim 48 wherein the second reaction gas is
provided through the inlet.
50. The method of claim 48 wherein the inlet is a first inlet and
wherein the second reaction gas is provided through a second
inlet.
51. The method of claim 50 wherein the second inlet passes through
the first chamber surface.
52. The method of claim 51 further comprising directionally-flowing
the second reaction gas away from the first surface toward the
chamber outlet, and wherein the second chamber surface opposes the
first chamber surface.
Description
TECHNICAL FIELD
[0001] The present invention pertains to CVD apparatuses and
methods for forming layers over a semiconductor substrate.
BACKGROUND OF THE INVENTION
[0002] Methods of chemical vapor deposition (CVD) are used to
produce thin layers of material during various industrial processes
including semiconductor device fabrication. CVD methods involve
introduction of vaporized precursor materials into a reactor,
adsorption of the vapor precursor materials onto a surface of a
semiconductor substrate and eventual incorporation of such
precursor materials into solid films.
[0003] Sequential introduction of various precursors into a CVD
apparatus may result in undesirable mixing of precursors in areas
of the apparatus other than on the semiconductor substrate, such as
within a common supply line or within the chamber itself. The first
precursor material is purged from the chamber after adsorption onto
the semiconductor substrate and prior to introduction of a second
precursor material to avoid undesirable mixing.
[0004] In conventional CVD processes incomplete purging may occur
due to precursor material becoming trapped within an area of the
reaction chamber. Such incomplete purging may result in unwanted
mixing of precursor materials upon the introduction of the second
precursor and may lead to adsorption of precursor materials and
adduct formation upon reaction chamber surfaces. Adduct materials
that form on the reaction chamber surfaces may precipitate onto the
substrate and cause defects in the thin layer formation.
[0005] Accordingly it is desirable to provide CVD apparatuses and
deposition methods that are designed to minimize unwanted mixing
and unwanted deposition of films onto apparatus surfaces.
BRIEF DESCRIPTION OF THE DRAWING
[0006] Preferred embodiments of the invention are described below
with reference to the following accompanying drawing.
[0007] The FIGURE shows a diagram of a deposition chamber and a
related process chemical delivery system according to an embodiment
of the present invention.
SUMMARY OF THE INVENTION
[0008] In one aspect, the invention encompasses a method of forming
a layer on a semiconductor substrate. A semiconductor substrate is
provided within a reaction chamber. The chamber has at least two
inlet ports extending therein. A first of the at least two inlet
ports terminates in a first opening which is a first distance from
the substrate. A second of the inlet ports terminates in a second
opening which is a second distance from the substrate. The second
distance is greater than the first distance. A first material is
flowed into the reaction chamber through the first inlet port. At
least a portion of the first material is deposited onto the
substrate to form the layer over the substrate. The reaction
chamber is purged by flowing an inert material into the reaction
chamber through the second inlet port.
[0009] In another aspect, the invention encompasses a method of
chemical vapor deposition. A substrate is provided within a
reaction chamber. The reaction chamber includes a lid. The reaction
chamber also includes a first valve assembly and a second valve
assembly. Each valve assembly includes a valve closure. The
reaction chamber also includes an inert material inlet port which
is distinct from the valve assemblies. The first and second valve
assemblies, as well as the inert material inlet port pass through
the lid of the reaction chamber. A first material is flowed into
the chamber through the first valve closure, and at least a portion
of this first material is deposited onto the substrate. The
reaction chamber is purged by flowing an inert material through the
inert material inlet port. The inert material passes through the
inert material inlet port and through a distribution head. The
distribution head is positioned within the reaction chamber between
the lid and the first and second valve closures. Once the first
material has been deposited, a second material is flowed into the
chamber through the second valve closure. At least a portion of the
second material is deposited onto the substrate.
[0010] In another aspect the invention encompasses a chemical vapor
deposition apparatus. The apparatus includes a deposition chamber
and a substrate platform. Two or more inlet ports extend into the
deposition chamber. A first of the inlet ports terminates in a
first opening which is a first distance from the substrate
platform. A second of the inlet ports terminates in a second
opening that is a second distance from the substrate platform. The
second distance is greater than the first distance. The apparatus
also includes a porous distribution head within the chamber located
between the first and second openings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0011] This disclosure of the invention is submitted in furtherance
of the constitutional purposes of the U.S. patent Laws "to promote
the progress of science and useful arts" (Article 1, Section
8).
[0012] The present invention is described with reference to the
FIGURE. A method of forming a layer 12 over a semiconductor
substrate 10 is shown. The semiconductor substrate 10 is provided
within an apparatus 8 comprising a reaction chamber 14. The
reaction chamber 14 has at least two inlet ports 16 and 20. A first
of the at least two inlet ports 16 terminates in a first opening 18
a first distance from the substrate. A second of the at least two
inlet ports 20 terminates in a second opening 22 a second distance
from the substrate. A first material 32 is flowed into the reaction
chamber 14 through the first inlet port 16. At least a portion of
first material 32 is deposited onto substrate 10 to form a layer
12.
[0013] An inert material 34 is flowed into the reaction chamber
through the second inlet port 20 to purge the reaction chamber. The
flowing of the inert material can occur while flowing the first
material. Alternatively, flowing the inert material may occur after
deposition of the first material or both during and after
deposition of the first material. The flow of inert material can be
pulsed or continuous. It is advantageous to continuously flow the
inert material while flowing the first material to assist in moving
the first material away from the area of the chamber around first
inlet port 16 and reduce adduct formation on reaction chamber
surfaces. It is also advantageous to purge the chamber by flowing
the inert material from an opening located a greater distance from
the substrate than the opening through which the first material is
provided to reduce, or even minimize retention of first material
within the reaction chamber.
[0014] The inert material 34 preferably comprises a fluid that is
inert to reaction with the substrate 10, with the first material
32, and with materials subsequently introduced into the chamber for
deposition. The inert material can comprise a gas. Exemplary gases
can be helium, argon or nitrogen or mixtures thereof. Preferably
when the inert material 34 comprises a gas, the gas is flowed into
the chamber at a rate no greater than about 100 standard cubic
centimeters per minute (sccm).
[0015] The second inlet port 20 can be behind the porous
distribution head 38. The distribution head 38 can be located
within the reaction chamber 14 between the first opening 18 and the
second opening 22. It is advantageous to provide the inert material
from behind a porous distribution head where the distribution head
is positioned between the first and the second openings to result
in a downward flow of inert material. The downward flow can both
minimize counter-flow of the first material and assist in the
diffusion of the first material over the substrate. In addition,
the downward flow can alleviate unwanted adsorption of first
material onto surfaces within the reaction chamber.
[0016] After deposition of the first material 32, a second material
36 can be flowed into the reaction chamber. The second material 36
is flowed into reaction chamber 14 through a third inlet port 24.
The third inlet port 24 terminates in a third opening 26 which is a
third distance from the substrate 10. The second distance is
greater than the third distance. At least a portion of the second
material 36 is deposited onto the substrate 10. It is advantageous
to flow the second material through an inlet port that is distinct
from the inlet port through which the first material passes rather
than through a common inlet port because unwanted mixing of the
first and second materials within an inlet port is thereby
minimized. It is to be understood, however, that the methods
described herein may be adapted to processes that provide a first
material and a second material through a common inlet port.
[0017] While flowing the second material, the reaction chamber may
again be purged by flowing an inert material through the second
inlet port as described above. Alternatively, the inert material
may be flowed after flowing the second material or both during and
after the flowing of the second material. A series of multiple
rounds of deposition of reactive materials onto the substrate,
accompanied either by a simultaneous flowing or by a subsequent
flowing of inert material through of the reaction chamber according
to the method described herein, are contemplated in the present
invention.
[0018] Numerous chemicals can be utilized for first material 32 and
for second material 36 for purposes of the present invention.
Exemplary combinations include a first material comprising
trimethyl aluminum and a second material comprising one or both of
water and ozone; or a first material comprising TiCl.sub.4 where
the second material comprises ammonia; or a first material
comprising Ta.sub.2O.sub.5 where the second material comprises
ammonia.
[0019] A second aspect of the invention encompassing a method of
chemical vapor deposition is described with reference to the
FIGURE. A substrate 10 is provided within a reaction chamber 14.
The reaction chamber 14 includes a lid 40, a first valve assembly
42 having a first valve closure 28, and a second valve assembly 44
having a second valve closure 30. An inert material inlet port 20
is provided into the reaction chamber 14, the inert material inlet
port 20 is being distinct from the valve assemblies 42 and 44. In
this aspect of the invention, one, two or all three of the first
valve assembly 42, the second valve assembly 44 and the inert
material inlet port 20 can pass through the lid 40. A first
material 32 is flowed into the reaction chamber 14 through the
first valve closure 28. At least a portion of the first material 32
is deposited onto the substrate 10.
[0020] After the first material 32 is deposited onto the substrate
10, the reaction chamber 14 and the valve closures 28, 30 are
purged by flowing an inert material 34 through the inert material
inlet port 20 into the reaction chamber. Alternatively, inert
material 34 can be flowed through the reaction chamber while
flowing first material 32. The inert material 34 is passed from the
inert material inlet port 20 through a distribution head 38. The
distribution head 38 is within the reaction chamber 14 and between
the lid 40 and the first and second valve closures. The purging of
the reaction chamber and valve closures can utilize, for example, a
distribution head 38 that is a gas dispersion head in combination
with an inert material 34 comprising a gas. The inert material is
removed from the reaction chamber through an outlet port 48.
[0021] After deposition of first material 32, a second material 36
can be flowed through the second valve closure 30 into the reaction
chamber 14. At least a portion of the second material 36 is
deposited onto the substrate 10. Inert material 34 can be flowed
into the reaction chamber simultaneously with the flowing of the
second material, can be flowed after the flowing of the second
material, or can be flowed both during and after the flowing of the
second material.
[0022] Still referring to the FIGURE, chemical vapor deposition
apparatus 8 includes a deposition chamber 14 and a substrate
platform 46. The apparatus 8 includes at least two inlet ports 16
and 20, and at least one outlet port 48, that extend into the
chamber 14. A first of the at least two inlet ports 16 terminates
in a first opening 18. There is a first distance between the
substrate platform 46 and the first opening 18. A second of the at
least two inlet ports 20 terminates in a second opening 22. There
is a second distance between the substrate platform 46 and the
second opening 22. The second distance is greater than the first
distance. The at least one outlet port 48 terminates in an opening
50. The apparatus 8 can also include a porous distribution head 38
within the chamber 14. The porous distribution head 38 is
positioned between the first opening 18 and the second opening
22.
[0023] The shown apparatus 8 includes a lid 40. The first inlet
port 16, or the second inlet port 20, or both can pass through the
lid, and in the shown embodiment, inlet ports 16 and 20 both pass
through the lid. In alternative embodiments, at least one of the
inlet ports can access the chamber through an area of apparatus 8
other than through the lid. For instance, one or more of inlet
ports 16 and 20, may pass through a chamber wall.
[0024] Outlet port 48 can access the chamber though the lid or
through areas of apparatus 8 other than the lid. It is advantageous
for the outlet port to access the chamber through a surface
opposing the surface through which at least the second inlet port
22 passes to assist in maintaining directional flow of precursor
gas away from the surface through which the second inlet port
passes. A directional flow can aid in removal of reactive materials
from the reaction chamber and thereby reduce or minimize adduct
formation on surfaces near the second inlet port and other surfaces
within the reaction chamber.
[0025] The porous distribution head 38 of the apparatus 8 is not
limited to a specific size and may, for example, extend across less
than the entire length of the chamber 14. One example of a
distribution head which may be utilized in the present invention is
a gas dispersion head.
[0026] The porous distribution head 38 of the present invention is
not limited to a specific material but may comprise, for example,
aluminum such as anodized aluminum. In addition, the size of the
distribution head pores 39 and the distance between the pores are
not limited to specific values. An exemplary pore diameter is about
0.040 inches. The distance between the pores of the distribution
head may be measured by the distance between the center point of
one pore and the center point of a neighboring pore. For purposes
of this invention, this center to center distance between pores can
be, for instance, a distance of not greater than about 0.100
inches.
[0027] In addition to the features described above, an apparatus
encompassed by the present invention may also include a third inlet
port 24. The third inlet port 24 terminates in a third opening 26
which is a third distance from the substrate platform 46. The third
distance is less than the second distance. In the shown embodiment,
the third inlet port 24 passes through the lid 40 of apparatus 8,
but can also enter the chamber though an alternative area of the
apparatus such as a chamber wall.
[0028] The distance between the first opening and the substrate
platform (the first distance) and the distance between the third
opening and the substrate platform (the third distance) are not
limited to specific values. The first and the third distance can be
equal. Either the first distance or the third distance or both are
preferably from about 28 mm to about 30 mm.
[0029] The second inlet port 22 of the apparatus can be located
behind the porous distribution head 38. The distribution head 38 is
within the reaction chamber 14 and between the first opening 18 and
the second opening 22 and, in embodiments comprising a third inlet
port, also between the second opening 22 and the third opening
26.
[0030] The inlet ports encompassed by the present invention are not
limited to any specific form. One or more of the inlet ports in the
apparatus may be comprised by a valve assembly 42 and 44. Further,
a valve assembly can comprise a valve closure 28, 30. The valve
closure is not intended to be limited to a specific mechanism and
can be, for instance, located at an opening that terminates an
inlet port 18, 26, such closure being capable of sealing access
from the respective inlet port into the reaction chamber 14.
[0031] An apparatus configuration wherein the inert material is
flowed from behind a porous distribution head, the distribution
head being farther from the substrate than the valve closure, is
advantageous because the downward flow of inert material can assist
in preventing counter-flow of first and second materials into the
opposite valve.
[0032] In the shown embodiment, valve assemblies 42 and 44 pass
through the lid 40. Alternatively, one or both of the valve
assemblies can access the chamber through other areas of the
apparatus 8. For instance, one or both of the valve assemblies can
pass though the chamber wall.
[0033] The advantages conferred by the present invention can make
the invention particularly suitable for processes where an
efficient purge is necessary to prevent unwanted mixing of reactive
chemicals and adduct formation upon exposed surfaces within a
reaction chamber. Such processes include atomic layer
deposition.
[0034] In compliance with the statute, the invention has been
described in language more or less specific as to structural and
methodical features. It is to be understood, however, that the
invention is not limited to the specific features shown and
described, since the means herein disclosed comprise preferred
forms of putting the invention into effect. The invention is,
therefore, claimed in any of its forms or modifications within the
proper scope of the appended claims appropriately interpreted in
accordance with the doctrine of equivalents.
* * * * *