U.S. patent application number 10/674302 was filed with the patent office on 2005-03-31 for method and apparatus for deposition & formation of metal silicides.
Invention is credited to Giewont, Kenneth John, Jones, Bradley Paul, Lavoie, Christian, Purtell, Robert J., Wang, Yun-Yu, Wong, Kwong Hon.
Application Number | 20050067745 10/674302 |
Document ID | / |
Family ID | 34376854 |
Filed Date | 2005-03-31 |
United States Patent
Application |
20050067745 |
Kind Code |
A1 |
Giewont, Kenneth John ; et
al. |
March 31, 2005 |
Method and apparatus for deposition & formation of metal
silicides
Abstract
Disclosed is a method and structure for forming a silicide on a
silicon material. The invention places the silicon material in a
vacuum environment, forms metal on the silicon material, and then
heats the silicon surface and the metal without breaking the vacuum
environment. The processes of forming the metal and heating the
silicon can be performed simultaneously without breaking the vacuum
environment to form the silicide as the metal is being deposited.
After the foregoing processing, the invention can remove the
silicon surface from the vacuum environment and perform additional
heating of the silicon surface. The first heating process forms a
monosilicide and the additional heating forms a disilicide.
Inventors: |
Giewont, Kenneth John;
(Hopewell Junction, NY) ; Jones, Bradley Paul;
(Pleasant Valley, NY) ; Lavoie, Christian;
(Ossining, NY) ; Purtell, Robert J.; (Mohogan
Lake, NY) ; Wang, Yun-Yu; (Poughquag, NY) ;
Wong, Kwong Hon; (Wappingers Falls, NY) |
Correspondence
Address: |
Frederick W. Gibb, III
McGinn & Gibb, PLLC
Suite 304
2568-A Riva Road
Annapolis
MD
21401
US
|
Family ID: |
34376854 |
Appl. No.: |
10/674302 |
Filed: |
September 30, 2003 |
Current U.S.
Class: |
266/250 |
Current CPC
Class: |
C23C 14/5806 20130101;
C23C 14/16 20130101 |
Class at
Publication: |
266/250 |
International
Class: |
C22F 001/00 |
Claims
What is claimed is:
1. A system for forming a silicide on a silicon material, said
system comprising: a vacuum chamber adapted to hold said silicon
material under a vacuum environment; a metal formation tool
connected to said vacuum chamber and being adapted to form metal on
said silicon material while said silicon material is under said
vacuum environment within said vacuum chamber; and a heating tool
connected to said vacuum chamber and being adapted to heat said
silicon while said silicon material is under said vacuum
environment within said vacuum chamber.
2. The system in claim 1, further comprising a etch tool external
to said vacuum chamber and being adapted to perform etching of said
metal after said silicon material is removed from said vacuum
chamber.
3. The system in claim 1, wherein said vacuum chamber comprises a
plurality of connected vacuum chambers adapted to maintain said
silicon material in a continuous vacuum environment while said
metal formation tool forms said metal and while said heating tool
heats said silicon material.
4. The system in claim 3, wherein said vacuum chambers comprise: a
first vacuum chamber to which said metal formation tool is
attached; a second vacuum chamber to which said heating tool is
attached; and a third vacuum chamber adapted to maintain said
vacuum environment while transporting said silicon material from
said first vacuum tool to said second vacuum tool.
5. The system in claim 1, wherein said heating tool is adapted to
heat said silicon material to temperatures between 300.degree. C.
and 400.degree. C. to form a metal rich silicide or between
temperatures of 450.degree. C. and 550.degree. C. to form a
monosilicide.
6. The system in claim 1, further comprising a second heating
tool.
7. The system in claim 6, wherein said second heating tool is
adapted to heat said silicon material to temperatures above
600.degree. C. to form a disilicide.
8. A system for forming a silicide on a silicon material, said
system comprising: a vacuum chamber adapted to hold said silicon
material under a vacuum environment; a metal formation tool
connected to said vacuum chamber and being adapted to deposit metal
on said silicon material while said silicon material is under said
vacuum environment within said vacuum chamber; and a heating tool
connected to said vacuum chamber and being adapted to heat said
silicon simultaneously while said metal formation tool forms said
metal on said silicon material such that a silicide material is
formed as said metal is deposited on said silicon materal.
9. The system in claim 8, wherein said heating tool comprises a
heated chuck within said vacuum chamber and is adapted to hold said
silicon materal.
10. The system in claim 9, wherein said heated chuck comprises a
resistive heater.
11. The system in claim 8, further comprising a etch tool external
to said vacuum chamber and being adapted to perform etching of said
metal after said silicon material is removed from said vacuum
chamber.
12. The system in claim 8, wherein said heating tool is adapted to
heat said silicon material to temperatures between 300.degree. C.
and 400.degree. C. to form a metal rich silicide or between
temperatures of 450.degree. C. and 550.degree. C. to form a
monosilicide.
13. The system in claim 8, further comprising a second heating
tool.
14. The system in claim 13, wherein said second heating tool is
adapted to heat said silicon material to temperatures above
600.degree. C. to form a disilicide.
15. A method of forming a silicide on a silicon material
comprising: placing said silicon material in vacuum environment;
forming metal on said silicon material without breaking said vacuum
environment; and heating said silicon surface and said metal
without breaking said vacuum environment.
16. The method in claim 15, further comprising performing
additional heating of said silicon surface.
17. The method in claim 16, wherein said heating forms a
monosilicide and said additional heating forms a disilicide.
18. The method in claim 16, wherein said heating is performed at
temperatures between 300.degree. C. and 400.degree. C. to form a
metal rich silicide or between temperatures of 450.degree. C. and
550.degree. C. to form a monosilicide, and said additional heating
is performed at temperatures above 600.degree. C. to form a
disilicide.
19. The method in claim 15, wherein said processes of forming said
metal and said heating of said silicon are performed simultaneously
without breaking said vacuum environment.
20. The method in claim 15, wherein said metal comprises one of
Cobalt and Nickel.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention generally relates to silicide
formation and more particularly to an improved method and system
that deposit metal and heats the silicon and metal without breaking
vacuum.
[0003] 2. Description of the Related Art
[0004] A silicide is often formed on silicon surfaces to decrease
resistivity of the silicon. More specifically, a metal is deposited
on the silicon surface and the structure is heated. This produces a
silicide on the silicon surface. Conventional systems first form
the metal and then move the structure to a heating tool to perform
the heating process. However, this allows ambient materials, such
as oxygen, to have a detrimental effect upon the metal that is used
in the silicide process. Therefore, conventional systems often form
a protective layer over the silicide metal. This protective layer
must eventually be removed.
[0005] The invention described below eliminates the need for this
protective layer (and its removal) by forming the metal and heating
the structure without breaking vacuum. Therefore, with the
invention described below, oxygen and other ambients are prevented
from affecting the metal used in the silicide process.
SUMMARY OF THE INVENTION
[0006] The invention provides methods and structures for forming a
silicide on a silicon material. The invention places the silicon
material in a vacuum environment, forms metal on the silicon
material, and then heats the silicon surface and the metal without
breaking the vacuum environment. The processes of forming the metal
and heating the silicon can be performed simultaneously without
breaking the vacuum environment to form the silicide as the metal
is being deposited. After the foregoing processing, the invention
can remove the silicon surface from the vacuum environment and
perform additional heating of the silicon surface. The first
heating process forms a monosilicide and the additional heating
forms a disilicide. More specifically, the first heating process is
performed at temperatures between 300.degree. C. and 400.degree. C.
to form a metal rich silicide or between temperatures of
450.degree. C. and 550.degree. C. to form a monosilicide, and the
additional heating is performed at temperatures above 600.degree.
C. to form a disilicide. The metal can comprise Cobalt, Nickel,
etc.
[0007] To perform the foregoing processing, the invention provides
a system that includes a vacuum chamber adapted to hold the silicon
material under a vacuum environment. A metal formation tool is
connected to the vacuum chamber and is adapted to form metal on the
silicon material while the silicon material is under the vacuum
environment within the vacuum chamber. Additionally, a heating tool
is connected to the vacuum chamber and adapted to heat the silicon
while the silicon material is under the vacuum environment within
the vacuum chamber.
[0008] In one embodiment, the heating tool heats the silicon
simultaneously while the metal formation tool deposits the metal on
the silicon material, so that a silicide material is formed as the
metal is deposited on the silicon material. In this embodiment, the
heating tool comprises a heated chuck having, for example, a
resistive heater.
[0009] The system can also include an etch tool (e.g., wet etch,
etc.) external to the vacuum chamber that performs wet etching of
the unreacted metal after the silicon material is removed from the
vacuum chamber. The system can further include a second heating
tool (possibly external to the vacuum chamber) that is adapted to
heat the silicon material after the silicon material is removed
from the vacuum chamber and after it undergoes the etching process.
This second heating tool is adapted to heat the silicon material to
temperatures above 600.degree. C. to form a disilicide.
[0010] The vacuum chamber can comprise a plurality of connected
vacuum chambers adapted to maintain the silicon material in a
continuous vacuum environment while the metal formation tool forms
the metal and while the heating tool heats the silicon material.
Thus, for example, the vacuum chambers can comprise a first vacuum
chamber to which the metal formation tool is attached, a second
vacuum chamber to which the heating tool is attached, and a third
vacuum chamber adapted to maintain the vacuum environment while
transporting the silicon material from the first vacuum tool to the
second vacuum tool.
[0011] These, and other, aspects and objects of the present
invention will be better appreciated and understood when considered
in conjunction with the following description and the accompanying
drawings. It should be understood, however, that the following
description, while indicating preferred embodiments of the present
invention and numerous specific details thereof, is given by way of
illustration and not of limitation. Many changes and modifications
may be made within the scope of the present invention without
departing from the spirit thereof, and the invention includes all
such modifications.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The invention will be better understood from the following
detailed description with reference to the drawings, in which:
[0013] FIG. 1 is a flow diagram illustrating a preferred method of
the invention;
[0014] FIG. 2 is a schematic diagram of a system according to the
invention;
[0015] FIG. 3 is a flow diagram illustrating a preferred method of
the invention; and
[0016] FIG. 4 is a schematic diagram of a system according to the
invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
[0017] The present invention and the various features and
advantageous details thereof are explained more fully with
reference to the non-limiting embodiments that are illustrated in
the accompanying drawings and detailed in the following
description. It should be noted that the features illustrated in
the drawings are not necessarily drawn to scale. Descriptions of
well-known components and processing techniques are omitted so as
to not unnecessarily obscure the present invention in detail.
[0018] As shown in the flowchart in FIG. 1, the invention provides
a method for forming a silicide on a silicon material. More
specifically, in item 100, the invention places the silicon
material in a vacuum environment. Then, in item 102, the invention
forms (e.g., deposits) metal on the silicon material without
breaking vacuum. Next, in item 104, the invention heats the silicon
surface and the metal without breaking the vacuum environment.
[0019] After the foregoing processing, the invention removes the
silicon surface from the vacuum environment (106) and performs a an
etching process 108 (e.g., wet etching, etc.) to clean off
unreacted metal and an additional heating process 110. The first
heating process 104 forms a monosilicide or metal rich silicide and
the additional heating forms a disilicide. More specifically, the
first heating process is performed at temperatures between
300.degree. C. and 400.degree. C. to form a metal rich silicide or
between temperatures of 450.degree. C. and 550.degree. C. to form a
monosilicide, and the additional heating 110 is performed at
temperatures above 600.degree. C. to form a disilicide. The metal
can comprise Cobalt, Nickel, etc.
[0020] The inventive system shown in FIG. 2 includes a vacuum
chamber system 200 adapted to hold the silicon material 210 under a
vacuum environment, using, for example chucks 216, 218. The vacuum
chamber system 200 can include a plurality of connected vacuum
chambers 202-204 adapted to maintain the silicon material 210 in a
continuous vacuum environment while the metal formation tool forms
the metal 212 and while the heating tool heats the silicon material
210 and the metal 212 to form a silicide 214. The vacuum system 200
is operated under a vacuum or with an inert gas, so the substrate
is not exposed to harmful ambients (e.g., air or O.sub.2).
[0021] Thus, for example, the vacuum chambers can comprise a first
vacuum chamber 202 containing the metal formation tool 206, a
second vacuum chamber 204 containing the heating tool 208, and a
third vacuum chamber 203 adapted to maintain the vacuum environment
while transporting the silicon material 210 from the first vacuum
tool to the second vacuum tool. This vacuum chamber system 200 is
merely exemplary and one ordinarily skilled in the art would
understand that any number of different vacuum system could be used
to maintain the silicon material 210 in a continuous vacuum
environment while the metal formation tool forms the metal 212 and
while the heating tool heats the silicon material 210.
[0022] Item 206 is an exemplary metal formation tool that is
connected to (within) the vacuum chamber 202 and that is adapted to
form metal 212 on the silicon material 210 while the silicon
material 210 is under the vacuum environment within the vacuum
chamber system 200. Item 208 illustrates the heating tool that is
within the vacuum chamber 204 and that is adapted to heat the
silicon while the silicon material 210 is under the vacuum
environment within the vacuum chamber system 200.
[0023] The inventive system also includes an etch tool 220 external
to the vacuum chamber system 200 that performs (wet) etching 108 of
the unreacted metal 214 after the silicon material 210 is removed
from the vacuum chamber system 200 (after vacuum is broken). A
second heating tool 222, which can be internal or external to the
vacuum chamber system 200, is adapted to heat the silicon material
210 after the etching process 108. This second heating tool is
adapted to heat the silicon material to temperatures above
600.degree. C. to form a disilicide.
[0024] Thus, the present invention forms, for example, Cobalt,
Nickel, etc. silicide on a silicon substrate. In item 102, the
invention deposits the metal 212 on the silicon in a vacuum process
chamber 200 at a low temperature (<300.degree. C.). The metal
212 can be, for example, Co, Ni, or other. The metal 212 can be
deposited as pure metal or a metal containing a small amount (e.g.,
20%) of Si, or the metal may have an overlying or underlying layer
of another metal (e.g., Ti, W, TiW) or metal nitride (e.g.,
TiN).
[0025] As shown above, the invention anneals the metal 104 to form
a metal silicide 214. The annealing chamber 202 is within the same
vacuum system 200 as the metal deposition chamber(s) 204, so the
wafer 210 is not exposed to the air between the metal deposition
104 and anneal 106. The anneal 106 may be at a low temperature
(300-450.degree. C.) that forms metal rich silicide (e.g.,
Co.sub.2Si) or medium temperature (450-550.degree. C.) that forms
monosilicide (CoSi). This process may be supplemented by the
conventional known process of removing unreacted metal (and
cap/underlayer, if used) from non-reactive portions (e.g., oxide)
of a patterned substrate during the wet etching 108. The second
annealing 110 is performed at a high temperature (>600.degree.
C.) to form disilicide (e.g., CoSi.sub.2).
[0026] In another embodiment, shown in the flowchart in FIG. 3, the
processes of forming the metal and heating the silicon are
performed simultaneously without breaking the vacuum environment to
form the silicide as the metal is being deposited. More
specifically, in item 300, the invention places the silicon
material in a vacuum environment. Then, in item 302, the invention
forms (e.g., deposits) metal on the silicon material without
breaking vacuum and simultaneously heats the silicon surface 210
and the metal 212 without breaking the vacuum environment. The
metal deposition and heating processes 302 are substantially
similar to those discussed above 102, 104 and reference is made to
that previous discussion for the details of this step. After the
foregoing processing, the invention again removes the silicon
surface from the vacuum environment (304) and performs a wet
etching process 306 and an additional heating process 308.
[0027] Thus, in this embodiment, the heating tool heats the silicon
simultaneously while the metal formation tool deposits the metal
212 on the silicon material 210, so that a silicide 214 material is
formed as the metal 212 is deposited on the silicon material 210.
As shown in FIG. 4, in this embodiment, the heating tool can
comprise a heated chuck 402 having, for example, a resistive
heater, within a vacuum chamber 400. Alternatively, any other
heating system 208 could be used with the vacuum chamber 400 to
perform the simultaneous heating and metal deposition.
[0028] As shown above, the invention provides a method and system
that deposits metal and heats silicon in a vacuum to avoid having
oxygen and other harmful ambients present when siliciding. This
eliminates the need to form protective barriers, thereby
eliminating many processing steps. This reduces costs, decreases
manufacturing processing time, and also increases yield as removing
processes decreases the chance that a defective process may
occur.
[0029] While the invention has been described in terms of preferred
embodiments, those skilled in the art will recognize that the
invention can be practiced with modification within the spirit and
scope of the appended claims.
* * * * *