U.S. patent application number 11/141018 was filed with the patent office on 2005-12-08 for vapor phase deposition apparatus, method for depositing thin film and method for manufacturing semiconductor device.
This patent application is currently assigned to NEC ELECTRONICS CORPORATION. Invention is credited to Iino, Tomohisa, Yamamoto, Tomoe.
Application Number | 20050268853 11/141018 |
Document ID | / |
Family ID | 35446299 |
Filed Date | 2005-12-08 |
United States Patent
Application |
20050268853 |
Kind Code |
A1 |
Yamamoto, Tomoe ; et
al. |
December 8, 2005 |
Vapor phase deposition apparatus, method for depositing thin film
and method for manufacturing semiconductor device
Abstract
A vapor phase deposition apparatus 100 for forming a thin film
comprising a chamber 1060, a piping unit 120 for supplying a source
material of the thin film into the chamber 1060 in a gaseous
condition, a vaporizer 202 for vaporizing the source material in a
source material container 112 and supplying the vaporized gas in
the piping unit 120 and a temperature control unit 180, is
presented. The temperature control unit 180 comprises: a first
temperature control unit 174, which is composed of a heater
controller unit 172 and a tape heater 170 and is capable of
controlling the temperature of the first piping 116 in the piping
unit 120 that is directly connected to the chamber 1060; a second
temperature control unit 176, which is composed of a heater
controller unit 168 and a tape heater 166 and is capable of
controlling the temperature of the second piping 114 that is
connected to the vaporizer; and a third temperature control unit
178, which is composed of a heater controller unit 167 and a
thermostatic chamber 153 and is capable of controlling the
temperature of the valve 159.
Inventors: |
Yamamoto, Tomoe; (Kanagawa,
JP) ; Iino, Tomohisa; (Kanagawa, JP) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W.
SUITE 800
WASHINGTON
DC
20037
US
|
Assignee: |
NEC ELECTRONICS CORPORATION
|
Family ID: |
35446299 |
Appl. No.: |
11/141018 |
Filed: |
June 1, 2005 |
Current U.S.
Class: |
118/726 |
Current CPC
Class: |
C23C 16/4485 20130101;
C23C 16/30 20130101; H01L 21/67103 20130101; H01L 21/67248
20130101; C23C 16/52 20130101; C23C 16/45544 20130101 |
Class at
Publication: |
118/726 |
International
Class: |
C23C 016/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 2, 2004 |
JP |
P2004-164124 |
Claims
What is claimed is:
1. A vapor phase deposition apparatus for forming a thin film,
comprising: a chamber; a vaporizing unit that vaporizes a source
material for said thin film to generate a source gas; a piping unit
provided between said chamber and said vaporizing unit; and a
temperature control unit that controls temperature of said piping
unit, wherein said piping unit includes: a first piping connected
to said chamber; a second piping connected to said vaporizing unit;
and a valve provided between said first piping and said second
piping, and wherein said temperature control unit is configured to
conduct a temperature control for said valve independently from at
least one of temperature controls for said first piping and for
said second piping.
2. The vapor phase deposition apparatus according to claim 1,
wherein said piping unit further comprises an exhaust unit between
said first piping and said second piping, said exhaust unit being
capable of exhausting said source gas.
3. The vapor phase deposition apparatus-according to claim 2,
wherein said exhaust unit is configured to exhaust said source gas
out from said second piping, when said first piping is blocked from
said second piping by said valve.
4. The vapor phase deposition apparatus according to claim 1,
wherein said temperature control unit is configured to provide
independent temperature controls for said first piping, said second
piping and said valve.
5. The vapor phase deposition apparatus according to claim 1,
wherein said temperature control unit is configured to control
temperatures of said first piping, said second piping and said
valve at substantially same temperature.
6. The vapor phase deposition apparatus according to claim 1,
wherein said temperature control unit is configured to control
temperatures of said first piping and said valve at substantially
same temperature and to control temperatures of said first piping
and of said valve at higher temperature than temperature of said
second piping.
7. The vapor phase deposition apparatus according to claim 1,
wherein said temperature control unit is configured to control
temperature of said first piping at higher temperature than
temperature of said valve, and to control temperature of said valve
at higher temperature than temperature of said second piping.
8. The vapor phase deposition apparatus according to claim 1,
wherein said temperature control unit is configured to control
temperature of said valve at a temperature, which is not lower than
a vaporizing temperature of said source gas and not higher than a
temperature that is higher by 20 degree C. than a decomposition
temperature of said source gas.
9. The vapor phase deposition apparatus according to claim 1,
wherein said vapor phase deposition apparatus is configured to
conduct an atomic layer deposition by alternately introducing two
or more types of gases for deposition sources into the chamber.
10. The vapor phase deposition apparatus according to claim 4,
wherein said vapor phase deposition apparatus is configured to
conduct an atomic layer deposition by alternately introducing two
or more types of gases for deposition sources into the chamber.
11. The vapor phase deposition apparatus according to claim 5,
wherein said vapor phase deposition apparatus is configured to
conduct an atomic layer deposition by alternately introducing two
or more types of gases for deposition sources into the chamber.
12. The vapor phase deposition apparatus according to claim 6,
wherein said vapor phase deposition apparatus is configured to
conduct an atomic layer deposition by alternately introducing two
or more types of gases for deposition sources into the chamber.
13. The vapor phase deposition apparatus according to claim 7,
wherein said vapor phase deposition apparatus is configured to
conduct an atomic layer deposition by alternately introducing two
or more types of gases for deposition sources into the chamber.
14. The vapor phase deposition apparatus according to claim 8,
wherein said vapor phase deposition apparatus is configured to
conduct an atomic layer deposition by alternately introducing two
or more types of gases for deposition sources into the chamber.
15. The vapor phase deposition apparatus according to claim 1,
wherein said vaporizing unit is configured to generate a source gas
by vaporizing a source containing a chemical compound containing Hf
or Zr.
16. The vapor phase deposition apparatus according to claim 9,
wherein said vaporizing unit is configured to generate a source gas
by vaporizing a source containing a chemical compound containing Hf
or Zr.
17. The vapor phase deposition apparatus according to claim 14,
wherein said vaporizing unit is configured to generate a source gas
by vaporizing a source containing a chemical compound containing Hf
or Zr.
18. The vapor phase deposition apparatus according to claim 1,
wherein said vaporizing unit is configured to generate a source gas
by vaporizing a source containing a chemical compound containing Zr
or Hf, N and hydrocarbon group.
19. A method for forming a thin film by employing said vapor phase
deposition apparatus according to claim 1, comprising: vaporizing a
source material by using said vaporizing unit to generate a source
gas; introducing said source gas from said vaporizing unit into
said chamber through said piping unit; and depositing a thin film
from said source gas in said chamber, wherein said introducing said
source gas further comprises controlling temperature of said valve
independently from at least one of said first piping and said
second piping by using said temperature control unit.
20. A method for manufacturing a semiconductor device by employing
said vapor phase deposition apparatus according to claim 1,
comprising: vaporizing a source material by using said vaporizing
unit to generate a source gas; introducing said source gas from
said vaporizing unit into said chamber through said piping unit;
and depositing a thin film from said source gas onto a
semiconductor substrate in said chamber, wherein said introducing
said source gas further comprises controlling temperature of said
valve independently from at least one of said first piping and said
second piping by using said temperature control unit.
Description
[0001] This application is based on Japanese patent application
NO.2004-164,124, the content of which is incorporated hereinto by
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a vapor phase deposition
apparatus, a method for depositing a thin film and a method for
manufacturing a semiconductor device.
[0004] 2. Related Art
[0005] In recent years, various innovations on methods for
supplying a source gas into a chamber, or in other words,
innovations on piping units, are actively made for the purpose of
providing a stable growth or deposition of a thin film having
improved quality with a vapor phase deposition apparatus. Typical
example of such techniques includes a technique disclosed in
Japanese Patent Laid-Open No. 2000-282,242.
[0006] Japanese Patent Laid-Open No. 2000-282,242 describes a
technique for controlling a temperature such that a temperature
through a piping from an outlet of a vaporizer to a chamber are
uniformity maintained in consideration of nature of a deposition
source gas to generate thin film.
SUMMARY OF THE INVENTION
[0007] However, it has now been discovered that an unwanted
phenomenon of generating particles on the deposited thin film has
often been found in the vapor phase deposition apparatus described
in Japanese Patent Laid-Open No. 2000-282,242. The present
inventors have investigated a cause thereof, and have found that
the phenomenon is occurred by the following reasons.
[0008] A valve is provided in a mid way of the piping that connects
the chamber to the vaporizer in the conventional vapor phase
deposition apparatus, for providing an appropriate process sequence
for depositing a thin film. In the conventional vapor phase
deposition apparatus, the temperatures of the whole piping are
controlled by one temperature control unit including such valve.
However, the valve has relatively larger volume, and thus has a
structure that is difficult to be heated. Therefore, it is
difficult to provide a sufficient heat to the interior of the valve
to maintain thereof at a preset temperature, and thus condensation
of the source gas is occurred. As a result, the structure thereof
includes a problem, which inherently promotes generating
particles.
[0009] According to the present invention, there is provided a
vapor phase deposition apparatus for forming a thin film,
comprising: a chamber; a vaporizing unit that vaporizes a source
material for the thin film to generate a source gas; a piping unit
provided between the chamber and the vaporizing unit; and a
temperature control unit that controls temperature of the piping
unit, wherein the piping unit includes: a first piping connected to
the chamber, a second piping connected to the vaporizing unit, and
a valve provided between the first piping and the second piping,
and wherein the temperature control unit is configured to conduct a
temperature control for the valve independently from at least one
of temperature controls for the first piping and for the second
piping.
[0010] The vapor phase deposition apparatus according to the
present invention is configured to be capable of conducting the
temperature control for the valve provided along the piping
connecting the chamber with the vaporizing unit independently from
the temperature control for the piping.
[0011] Such configuration allows maintaining the temperature in the
valve at desirably higher temperature. Thus, the condensation of
the source gas in the valve is inhibited, and the generation of the
particles on the thin film is inhibited.
[0012] According to the present invention, there is provided a
method for forming a thin film by employing the vapor phase
deposition apparatus according to the present invention,
comprising: vaporizing a source material by the vaporizing unit to
generate a source gas; introducing the source gas from the
vaporizing unit into the chamber through the piping unit; and
depositing a thin film from the source gas in the chamber, wherein
the introducing the source gas further comprises controlling
temperature of the valve independently from at least one of the
first piping and the second piping by using the temperature control
unit.
[0013] According to the present invention, there is provided a
method for manufacturing a semiconductor device by employing the
vapor phase deposition apparatus according to the present
invention, comprising: vaporizing a source material by using the
vaporizing unit to generate a source gas; introducing the source
gas from the vaporizing unit into the chamber through the piping
unit; and depositing a thin film with the source gas onto a
semiconductor substrate in the chamber, wherein the introducing the
source gas further comprises controlling temperature of the valve
independently from at least one of the first piping and the second
piping by using the temperature control unit.
[0014] Since, in the method for forming the thin film and the
method for manufacturing the semiconductor device according to the
present invention, the vapor phase deposition apparatus comprising
the above-described configuration is employed, the temperature in
the valve can be maintained at desirably higher temperature. Thus,
the condensation of the source gas in the valve is inhibited, and
the generation of the particles on the thin film is inhibited. As a
result, the thin film and the semiconductor device having improved
quality can be stably obtained.
[0015] While the aspects of present invention have been described
as above, it is to be understood that any combination of such
aspects is also included in the scope of the present invention. In
addition, any conversion of the expressions included in the present
invention into another category is also duly included in the scope
of the present invention.
[0016] According to the present invention, the generation of the
particles during the deposition of the thin film in the vapor phase
deposition apparatus can be inhibited.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The above and other objects, advantages and features of the
present invention will be more apparent from the following
description taken in conjunction with the accompanying drawings, in
which:
[0018] FIG. 1 is a schematic cross-sectional view of a vapor phase
deposition apparatus of an embodiment according to the present
invention, illustrating a configuration in introducing a first
source gas;
[0019] FIG. 2 is a schematic cross-sectional view of the vapor
phase deposition apparatus of the embodiment according to the
present invention, illustrating a configuration in introducing a
purge gas;
[0020] FIG. 3 is a schematic cross-sectional view of the vapor
phase deposition apparatus of the embodiment according to the
present invention, illustrating a configuration in introducing a
second source gas;
[0021] FIG. 4 is a schematic cross-sectional view of the vapor
phase deposition apparatus of the embodiment according to the
present invention, illustrating a configuration in introducing a
first source gas;
[0022] FIG. 5 is a chart, showing an example of a process sequence
for manufacturing a thin film by employing the vapor phase
deposition apparatus according to the embodiment;
[0023] FIG. 6 is a graph, showing a relationship of the valve
temperature with number of particles in the case of forming the
thin film with TEMAZ gas;
[0024] FIG. 7 is a graph, showing a relationship of the valve
temperature with number of particles in the case of forming the
thin film with various types of gases;
[0025] FIG. 8A is a time chart for illustrating a process sequence
for depositing an oxide film;
[0026] FIG. 8B is a time chart for illustrating a process sequence
for depositing an oxynitride film;
[0027] FIG. 9 is a schematic cross-sectional view showing a
configuration of a transistor according to the embodiment;
[0028] FIGS. 10A to 10D are cross-sectional views, for describing a
manufacturing process for the transistor according to the
embodiment;
[0029] FIGS. 11E and 11F are cross-sectional views, for describing
a manufacturing process for the transistor according to the
embodiment; and
[0030] FIG. 12 is a cross-sectional view, for describing a
manufacturing process for a capacitor according to the
embodiment.
DETAILED DESCRIPTION OF THE INVENTION
[0031] The invention will be now described herein with reference to
illustrative embodiments. Those skilled in the art will recognize
that many alternative embodiments can be accomplished using the
teachings of the present invention and that the invention is not
limited to the embodiments illustrated for explanatory
purposed.
[0032] Embodiments according to the present invention will be
described as follows in further detail, in reference to the annexed
figures. In all figures, identical numeral is assigned to an
element commonly appeared in the figures, and the detailed
description thereof will not be presented.
First Embodiment
[0033] FIG. 1 shows a vapor phase deposition apparatus according to
the present embodiment.
[0034] The vapor phase deposition apparatus 100 according to the
present embodiment is a type of a vapor phase deposition apparatus
for forming a thin film, and comprises a chamber 1060, a vaporizing
unit (source supplying section 1120) that is capable of vaporizing
a source material for thin film to generate a source gas, a piping
unit 120 provided between the chamber and the vaporizing unit and a
temperature control unit 180 for controlling the temperature of the
piping unit 120.
[0035] The piping unit 120 comprises a first piping 116 connected
to the chamber 1060, a second piping 114 connected to the
vaporizing unit and a valve 159 provided between the first piping
116 and the second piping 114.
[0036] The temperature control unit 180 includes a first
temperature control unit 174 that is capable of controlling the
temperature of the first piping 116 connected to the chamber 1060
among the piping unit 120 and comprises a heater controller unit
172 and a tape heater 170, a second temperature control unit 176
that is capable of controlling the temperature of the second piping
114 connected to the vaporizer and comprises a heater controller
unit 168 and a tape heater 166, and a third temperature control
unit 178 that is capable of controlling the temperature of the
valve 159 and comprises a heater controller unit 167 and a
thermostatic chamber 153.
[0037] The temperature control unit 180 is configured to control
the temperature of the valve 159 independently from the temperature
controls for at least one of the first piping 116 and the second
piping 114.
[0038] Since the vapor phase deposition apparatus 100 according to
the present embodiment has the above-described configuration, the
temperature in the valve can be maintained at desirably higher
temperature. Thus, the condensation of the source gas (process gas)
in the valve 159 is inhibited, and the generation of the particles
on the thin film is inhibited.
[0039] More specifically, the vapor phase deposition apparatus 100
comprises a chamber 1060 surrounded by chamber walls 106, a source
supplying unit 1120 and a piping unit 120 provided therebetween.
The source supplying unit 1120 is maintained at a room temperature,
and includes a source container 112, which is capable of storing
therein a source material such as tetraethyl methyl amino zirconium
(TEMAZ) in a liquid condition, and the source material is supplied
into a vaporizer 202 through the piping 118. The temperature
control of the vaporizer 202 is conducted by a temperature control
unit 204. Further, while the present embodiment illustrates the
exemplary configuration that the temperature of the source
container 112 is not under any control and spontaneously maintained
at the room temperature, another configuration of conducting
temperature control for the source container 112 may also be
employed.
[0040] The piping unit 120 comprises the first piping 116 connected
to the chamber 1060 and the second piping 114 connected to the
vaporizer 202, and the second piping 114 is connected to the first
piping 116 via the valve 159. In the present embodiment, the valve
159 is a three-way valve, and one port, which is not connected to
the second piping 114 or the first piping 116, is connected to a
source exhaust pipe 210 functioning as a source exhaust unit, and a
source exhaust 212 is provided at a further location. The presences
of the valve 159 and the source exhaust unit allow exhausting the
residual source material remaining within the second piping 114 to
the outside of the piping unit 120 while the source material is not
supplied into the chamber 1060. Therefore, a decomposition of the
residual source material remaining within the second piping 114 can
be inhibited.
[0041] Further, in the piping unit 120, the tape heater 170 is
provided around the first piping 116 that is connected to the
chamber 1060. The tape heater 170 is controlled by the heater
controller unit 172. Similarly, the tape heater 166 is provided
around the second piping 114 that is connected to the vaporizer
202. The tape heater 166 is controlled by the heater controller
unit 168.
[0042] In addition, the valve 159 is housed within a thermostatic
chamber 153 (having an equivalent temperature control-ability as
the tape heater has) separately from the tape heater 170 and the
tape heater 166, and is controlled by the heater controller unit
167. In that way, the temperature of the valve 159 can be suitably
controlled independently from the temperatures of the second piping
114 and the first piping 116, and the temperatures of the second
piping 114 and the first piping 116 can also be independently
controlled. Therefore, a quantity of heat supplied to the valve 159
can be selected to be different from the quantity of heat supplied
to the second piping 114 and the first piping 116. More
specifically, larger quantity of heat, which is larger than the
heat supplied to the second piping 114 and the first piping 116,
can be supplied to the valve 159, which is otherwise relatively
easier to be cooled as compared with the second piping 114 and the
first piping 116. Therefore, the decrease of the temperature of the
valve 159 down to a level that is lower than the temperatures of
the second piping 114 and the first piping 116 can be
prevented.
[0043] A source material for depositing the thin film (for example,
TEMAZ) is transferred from the source material container 112 though
the piping 118 and introduced into the vaporizer 202 in a form of a
liquid, and the introduced source material is heated to be
vaporized in the vaporizer 202.
[0044] The TEMAZ gas that is vaporized in the vaporizer 202 is then
transferred through the second piping 114, the valve 159 and the
first piping 116, and then introduced into the chamber 1060 from
perforations 110 of a showerhead 108 of the chamber 1060.
[0045] The interior of the chamber 1060 is provided with a
supporting member 102 comprising a heater 103, on which a
semiconductor wafer 104, for example, is mounted and heated. The
above-mentioned source gas and other source gases, an oxidizing gas
and a purge gas are sprayed from the perforations 110 of the shower
head 108 in accordance with a predetermined sequence to deposit a
thin film on the semiconductor wafer 104.
[0046] In addition, in the lower part of the chamber 1060 is
provided with an outlet piping 144 and an outlet port 146
communicated with the outlet piping 144 to form a configuration of
exhausting is the gas that has been introduced into the chamber
1060. A valve 158 is provided along the outlet piping 144 to
provide a control for opening and closing of the outlet piping 144.
The outlet piping 144 is branched at the valve 158 into an outlet
piping 140 in vicinity of the chamber and an outlet piping 142
remote from the chamber.
[0047] The shower head 108 is provided with a source material
supplying piping 130, which is communicated to the source material
container 122. A piping 126, which is provided with a valve 154 and
connected to the chamber, is provided in the source material
supplying piping 130. The piping 124 remote from the chamber, which
is connected to the source material container 122, is provided in
the opposite side of the shower head 108 opposite to the valve 154
in the source material supplying piping 130.
[0048] Further, the shower head 108 is communicated with a purge
gas inlet 138 through a purge gas supplying piping 136. The purge
gas supplying piping 136 is provided with a valve 156. A piping 132
extended between the valve 156 and the shower head 108 constitutes
one side of the purge gas supplying piping 136 on the
chamber-proximal side. A piping 134 extended between the valve 156
and purge gas inlet 138 also constitutes the other side of the
purge gas supplying piping 136 on the chamber-remote side.
[0049] A process sequence for manufacturing a thin film using such
vapor phase deposition apparatus will be described. FIG. 5 is a
timing chart, showing an example of a process sequence for
manufacturing a thin film by employing a vapor phase deposition
apparatus 100 according to the first embodiment.
[0050] As described above, a first source gas ("gasA") is
introduced to deposit a thin film by using the vapor phase
deposition apparatus 100 in accordance with an operation shown in
FIG. 1, as a first forming process step (step 1). Next, a purge gas
("purge") is introduced in accordance with FIG. 2, as a second
forming process step (step 2). Then, a second source gas ("gas B")
is introduced in accordance with FIG. 3, as a third forming process
step (step 3). Subsequently, a purge gas ("purge") is introduced in
accordance with FIG. 4, as a fourth forming process step (step 4).
Operations in accordance with FIG. 1 to FIG. 3 will be described
later.
[0051] Repetition of the deposition using a chemical vapor
deposition (CVD) or an atomic layer deposition (ALD) is conducted
by repeating such sequence to obtain a thin film having a desired
film thickness. In such case, repetition number of the sequence may
be suitably selected and other additional forming processes may be
included; depending upon the purposes.
[0052] More specifically, an exemplary example may be conducted in
accordance with a process sequence of, for example, FIG. 8A or FIG.
8B. FIG. 8A is a timing chart, showing an example of a process
sequence for depositing an oxide film, and FIG. 8B is a timing
chart, showing an example of a process sequence for depositing an
oxynitride film. In the sequence shown in FIG. 8B, the oxynitride
film is deposited by additionally introducing ammonia in the
deposition process.
[0053] In FIG. 8A and FIG. 8B, "DEPOSITION GAS" indicates a source
gas for a metal compound, and "OXIDIZING AGENT" indicates oxygen or
a gaseous chemical compound containing oxygen. An example of the
process sequence illustrated in FIG. 8A, employing
Zr(N(CH.sub.3)(C.sub.2H.sub.5)).sub.4 for the deposition gas,
nitric monoxide (NO) for the gaseous oxidizing agent and an inert
gas for the purge gas, will be described below.
[0054] Firstly, Zr(N (CH.sub.3)(C.sub.2H.sub.5)).sub.4 is supplied
into a chamber of an ALD apparatus as a source material to cause a
chemical reaction with a surface of a lower electrode, thereby
depositing a single atomic layer thereon. Next, the supply of
Zr(N(CH.sub.3)(C.sub.2H.sub.5))- .sub.4 is stopped, and then, an
inert gas, typical example of which include N.sub.2, Ar or the
like, is introduced into the chamber as a purge gas to purge or
flush the excess amount of unreacted
Zr(N(CH.sub.3)(C.sub.2H.sub.5)).sub.4 out.
[0055] Then, NO is supplied therein to remove functional group that
terminates Zr deposited on the substrate. Then, the supply of NO is
stopped, and an inert gas, typical example of which include
N.sub.2, Ar or the like, is introduced therein as a purge gas to
purge or flush unreacted NO and/or reaction byproducts, and then
the supply of the purge gas is stopped.
[0056] As described above, a desired number of the sequential
process cycle consisting of the supply of Zr(N
(CH.sub.3)(C.sub.2H.sub.5)).sub.4, the first purge, the supply of
NO and the second purge are repeated to obtain a high dielectric
constant film providing lower leakage current and having better
film quality, consisting of ZrO.sub.xC.sub.yN.sub.z having a film
thickness of 5 to 15 nm (where x, y and z are selected so as to
satisfy 0<x, 0.1.ltoreq.y.ltoreq.1.25, 0.01.ltoreq.z and
x+y+z=2).
[0057] Next, status of an operation for depositing a thin film on
the semiconductor wafer employing the vapor phase deposition
apparatus 100 shown in FIG. 1 according to the present embodiment
will be described. It is noted that FIG. 1 illustrates a status of
opening and closing the valve, which corresponds to the status in
the step 1 shown in FIG. 5. The opening/closing status of the valve
is distinguished in the figures by means of providing pattern, and
more specifically, a patterned valve indicates to be in the closing
status, and unpatterned valve indicates to be in the opening
status. TEMAZ gas, which is generated by being vaporized in the
vaporizer 202, is supplied to the chamber 1060 through the piping
unit 120, and introduced into the reaction chamber 1060 via the
perforations 110 of the shower head 108.
[0058] The first source gas (TEMAZ gas) introduced in the chamber
1060 reacts with an upper portion of the wafer 104 mounted on the
supporting member 102. Since the valve 158 is opened, byproducts
generated after the reaction and the unreacted source gas are
transferred through the outlet piping 140, the valve 158 and the
outlet piping 142 in this order and are eventually exhausted out
from the outlet port 146 In this occasion, since the valve 154
along the source material supplying piping 130 is closed, a second
source gas, description of which will be made later, is not
supplied. In addition, since the valve 156 along the purge gas
supplying piping 136 is also closed, a purge gas, description of
which will be made later, is not supplied.
[0059] Here, while the source material in the source material
container 112 is not particularly limited in the step 1, when high
dielectric constant film is formed, a source material containing a
chemical compound including Hf or Zr, such as HfO.sub.2, ZrO.sub.2
and the like, for example, may be preferably employed.
[0060] Particularly preferable chemical compound including Hf or Zr
may be a chemical compound containing Hf or Zr, N and a hydrocarbon
group, and the source material containing such compound may be
preferably employed. Such chemical compound may be, for example, a
compound having a general formula of: M(NRR').sub.4 (where M
contains at least one of Hf and Zr, and R and R' are same or
different hydrocarbon group(s)). R and R' may preferably be alkyl
group having 6 or less carbons/carbon, and more specifically,
methyl group, ethyl group, propyl group, tertiary butyl group or
the like may be employed. The use of such compounds provides stable
deposition of the high dielectric constant film. In addition, the
use of such compounds also inhibits a contamination of particles
derived from the source material of the deposition gas, and thus
further improvement in the film quality of the deposited high
dielectric constant film can be achieved.
[0061] More specifically, the preferable compounds may be:
Zr(N(C.sub.2H.sub.5).sub.2).sub.4 (tetra diethyl amino zirconium,
TDEAZ) or Zr(NCH.sub.3C.sub.2H.sub.5).sub.4 (TEMAZ) or the like.
Selection of such chemical compounds may provide a film having a
flat and smooth surface, and prevent a contamination of particles
in the film. As a result, the high dielectric constant film
providing lower leakage current and having better film quality can
be obtained.
[0062] CVD or ALD are conducted via the later-described process
utilizing the above-described source materials, so that a thin film
comprising ZrO.sub.xC.sub.yN.sub.z (where x, y and z are selected
to satisfy 0<x, 0.1.ltoreq.y.ltoreq.1.25, 0.01.ltoreq.z and
x+y.degree.z=2) is obtained. Thin film having such specified
composition provides higher capacity and is considerably reduced
leakage current. Therefore, the film can be preferably employed for
a capacitor film in a capacitance device, a gate insulating film in
a gate electrode of a transistor and the like.
[0063] FIG. 2 schematically illustrates a status of the vapor phase
deposition apparatus 100 according to the present embodiment during
the introduction of the purge gas in the step 2 and the step 4
shown in FIG. 5. After completing the introduction of the first
source gas shown in FIG. 1, a purge gas is introduced therein, as
shown in FIG. 2. The vapor phase deposition apparatus 100 shown in
FIG. 2 has substantially the same configuration as the
configuration of the vapor phase deposition apparatus 100 shown in
FIG. 1, except that the valve 159 in the piping unit 120
communicates with the source material outlet piping 210. Thus, the
supply of the first source gas into the chamber 1060 is stopped.
Therefore, when the valve 159 is closing the communication between
the second piping 114 and the first piping 116, the first source
gas remaining in the second piping 114 can be exhausted to the
outside of the piping unit 120. Therefore, a decomposition of the
residual first source gas remaining in the second piping 114 can be
inhibited.
[0064] On the other hand, since the valve 156 along the purge gas
supplying piping 136 is opened, the purge gas remaining in the
purge gas inlet 138 is transported through the piping 134, the
valve 156 and the piping 132 in this order, and is introduced into
the chamber 1060 surrounded by the chamber walls 106 from the
perforations 110 of the shower head 108.
[0065] Since the valve 158 is opened, the purge gas introduced into
the chamber 1060 flushes or purges the residual first source gas
remained in the chamber 1060 out, and the flushed residual first
source gas is transported through the outlet piping 140, the valve
158 and the outlet piping 142 in this order to be exhausted from
the outlet port 146.
[0066] FIG. 3 schematically illustrates a status of the vapor phase
deposition apparatus 100 according to the present embodiment during
the introduction of the second source gas. The introduction of the
second source gas corresponds to the step 3 in FIG. 5. After
completing the introduction of the purge gas shown in FIG. 2, the
second source gas is introduced therein, as shown in FIG. 3. The
vapor phase deposition apparatus 100 shown in FIG. 3 has
substantially the same configuration as the configuration of the
vapor phase deposition apparatus 100 shown in FIG. 1, except that
the valve 159 in the piping unit 120 communicates with the source
material outlet piping 210. Thus, the supply of the first source
gas into the chamber 1060 is stopped.
[0067] Further, the Valve 156 along the purge gas supplying piping
136 is also closed. Thus, the supply of the purge gas is also
stopped.
[0068] On the other hand, since the valve 154 along the source
material supplying piping 130 is opened, the second source gas
contained in the second source material container 122 is
transported through the piping 124, the valve 154 and the piping
126 in this order, and is introduced into the chamber 1060 from the
perforations 110 of the shower head 108.
[0069] The second source gas introduced in the chamber 1060 reacts
with an upper portion of the wafer 104 mounted on the supporting
member 102. Since the valve 158 is opened, byproducts after
reaction and unreacted second source gas are transferred through
the outlet piping 140, the valve 158 and the outlet piping 142 in
this order and are eventually exhausted via the outlet port
146.
[0070] When the thin film having higher dielectric constant is
formed by utilizing a source gas containing a chemical compound
including Hf or Zr as a first source gas, it is preferable to
employ an oxidizing gas as the second source gas. Typical oxidizing
gas includes oxygen or a chemical compound including oxygen. More
specifically, the typical compounds may be NO, NO.sub.2, N.sub.2O,
O.sub.2, O.sub.3 and the like. Among the compounds, NO, NO.sub.2
and N.sub.2O are preferable, and a gaseous mixture of NO and
NO.sub.2 and a gaseous mixture NO and O.sub.3, which represent
combinations of nitriding gas and oxidizing gas, are relatively
more preferable.
[0071] Stable deposition of the high dielectric constant film
having better film quality can be obtained by selecting such
compounds. Further, while H.sub.2O is comparatively easier to be
remained within the chamber 1060 in the process employing H.sub.2O
that has been frequently employed as an oxidizing gas, NO, N.sub.2O
and NO.sub.2 are easier to be removed from the inside of the
chamber 1060 by purging, thereby improving the manufacturing
efficiency.
[0072] When the first source gas is metal containing deposition gas
and the second source gas is an oxidizing gas, it is preferable to
select the volumetric ratio of these compounds (that is, metal
containing deposition gas/oxidizing gas) is equal to or less than
centesimal ({fraction (1/100)}). Such volumetric ratio helps
reducing impurities contained in the film.
[0073] When a gaseous mixture of NO and NO.sub.2 is employed as an
oxidizing gas, ratio of NO/NO.sub.2 is preferably equal to or less
than {fraction (1/10000)}. The pressure in the deposition process
is, for example, within a range of from 10 mTorr to 10 Torr.
[0074] After the second source material is introduced into the
chamber 1060, in the step 4 shown in FIG. 5, the purge gas is
introduced in chamber and is then exhausted, as indicated in FIG. 2
The above-mentioned four steps are repeated by several ten times to
several hundred times to deposit a film. In other words, the first
source gas and the second source gas, which are different
deposition source material, are alternately introduced into the
chamber 1060 to grow an atomic layer deposition, thereby depositing
a film.
[0075] Here, the deposition temperature for depositing the thin
film on the upper portion of the wafer 104 mounted on the
supporting member 102 in the case of employing Zr(NRR').sub.4 as
the source material may be preferably 200 degree C. to 400 degree
C., in both occasions of supplying the deposition gas including
Zr(NRR').sub.4 and supplying the oxidizing gas described later.
Contamination of the impurity to the thin film can be inhibited by
selecting the deposition temperature of not lower than 200 degree
C. Further, particle size of the crystallized particle is small and
the leakage current can be reduced by selecting the deposition
temperature of not higher than 400 degree C. The temperatures are
controlled by the heater 103 provided within the supporting member
102.
[0076] The first source material having properties shown in the
following Table 1 is mainly employed in the vapor phase deposition
apparatus 100 according to the present embodiment, and thus the
cases utilizing such material will be described below.
1TABLE 1 (degree C.) DECOM- DECOM- VAPORIZING POSITION POSITION
TEMPERATURE TEMPERA- TEMPERA- (T1) @ TURE TURE 0.1 Torr (T2) (T3)
T2 - T1 TEMAZ 76 85 130 9 TDEAZ 79 90 140 11 TEMAH 83 95 140 12
TDEAH 96 105 150 9
[0077] Here, "TEMAH" is an abbreviation of tetraethyl methyl amino
hafnium, and "TDEAH" is an abbreviation of tetra diethyl amino
hafnium.
[0078] A decomposition temperature (T3) is defined as a
temperature, at which a change of color (change in quality) is
caused in a moment of time due to a decomposition of the source
material, and a decomposition temperature (T2) is defined as a
temperature, at which a very lower level of a decomposition is
caused and a detection of a lower amount of particles is started in
the deposition process due to the very lower level of a
decomposition. Larger amount of the decomposition is occurred at
the temperature of T3 than that at the temperature of T2. The
"decomposition temperature" indicates T2 in the following
descriptions, unless otherwise instructed.
[0079] Results of the measurements for the temperatures of the
second piping 114, the first piping 116 and the valve 159 in the
vapor phase deposition apparatus 100 according to the present
embodiment, in the case that the power applied to the valve 159
along the piping unit 120 for supplying the first source material
is changed, are shown in Table 2.
2TABLE 2 FIRST PIPING POWER 7 8 9 10 11 12 116 and PRESET SECOND
(W) PIPING 114 MEASURED 70 80 90 100 110 120 TEMPERATURE (degree
C.) VALVE 159 POWER 10 11 12 13 14 15 PRESET (W) MEASURED 70 80 90
100 110 120 TEMPERATURE (degree C.)
[0080] The temperature of the valve 159 could be maintained to be
substantially the same as the temperatures of the second piping 114
and the first piping 116, only after applying higher electric power
to the temperature control unit than the power applied to the
second piping 114 and the first piping 116.
[0081] Concerning the temperature of the vaporizer 202 in the case
of employing TEMAZ as the first source material, since a vaporizing
temperature thereof (T1) at 0.1 Torr is76 degree C. and a
decomposition temperature thereof (T2) is 85 degree C., the
temperature of the vaporizer is controlled within a range of from
60 degree C. to 85 degree C, for example. Here, the vaporization
thereof can be occurred even if the temperature of the vaporizer
202 is lower than the vaporizing temperature (T1) of the source
material to some extent, and thus the source gas can be supplied
under such condition. Further, the temperature of the piping unit
120 is controlled to be higher than the temperature of the vicinity
of the vaporizer outlet port.
[0082] Since the decomposition temperature (T2) of TEMAZ that is a
critical temperature for generating the particles is 85 degree C.
and the vaporization temperature (T1) thereof is 76 degree C., the
temperature of the valve 159 provided along the piping unit 120 is
controlled within a range of from 80 degree to 100 degree, for
example. More specifically, such temperature is controlled to be
within a range of from a temperature that is not lower than the
vaporization temperature (T1) to a temperature that is the
decomposition temperature (T2) plus 20 degree C. Values of electric
power presets for respective temperature control units (that is,
the first temperature control unit 174, the second temperature
control unit 176 and the third temperature control section 178) and
the corresponding measured temperatures are shown in Table 3.
3 TABLE 3 FIRST SECOND PIPING PIPING VAPORIZER 116 VALVE 159 114
202 EXAMPLE 1 POWER 9 12 9 -- PRESET (W) MEASURED 90 90 90 80
TEMPERATURE (degree C.) EXAMPLE 2 POWER 8 11 8 -- PRESET (W)
MEASURED 80 80 80 80 TEMPERATURE (degree C.) EXAMPLE 3 MEASURED 90
90 85 80 TEMPERATURE (degree C.) EXAMPLE 4 MEASURED 95 90 85 80
TEMPERATURE (degree C.)
[0083] Example 1 represents a case that all the temperatures in the
piping unit 120 are equal and higher than the temperature of the
vaporizer 202, Example 2 represents a case that the temperature of
the vaporizer 202 and the temperatures in the piping unit 120 are
equal, Example 3 represents a case that the temperature of the
valve 159 is equal to the temperature of the first piping 116 and a
temperature gradient is generated from the vaporizer 202 to the
chamber 1060 in the control temperatures, and Example 4 represents
a case that a temperature gradient is generated for all the control
temperatures from the vaporizer 202 to the chamber 1060. While
there may be a case where the piping temperature on the side of the
chamber 1060 is higher than the decomposition temperature, the
source gas usually flows toward the chamber 1060 or the outlet port
212 and thus the immediate decomposition of the source material
hardly occurs even if the temperature therein is higher than the
decomposition temperature. Therefore, the condensation of the
source material can be inhibited while inhibiting the decomposition
of the source material in each of the above-described cases, that
are, the case that all the temperatures of the first piping 116,
the valve 159 and the second piping 114 are equal (Example 1 and
Example 2), the case that the temperature of the first piping 116
is equal to the temperature of the valve 159 and the temperature of
the first piping 116 and the temperature of valve 159 are higher
than the temperature of the second piping 114 (Example 3) and the
case that the temperature of the first piping 116 is higher than
the temperature of the valve 159 and the temperature of the valve
159 is higher than the temperature of the second piping 114
(Example 4).
[0084] Here, the preset temperatures may more preferably form a
temperature gradient that gradually elevates from the vaporizer 202
to the first piping 116. This is because, even though there is an
insufficiently heated portion in the respective parts (second
piping 114, valve 159 and first piping 116), the condensation of
the source material in the insufficiently heated portion can be
inhibited by setting higher temperature than the vaporizer 202.
Further, it is preferable to control the first piping 116 to
maintain the temperature of the first piping 116 that is
sufficiently high but not higher than the decomposition temperature
of the source material, since the purge in the pipings can be
easily carried out at such temperature, and further, even if the
source material is remained within the piping, the generation of
the particles due to the decomposition of the residual source
material by the passage of time or due to the mixing of the gases
released within the chamber 1060 by an inappropriate step in the
deposition process can be avoided. In these reasons, the case of
the Example 4 is more preferable shown in Table 3, for example.
[0085] An experiment for investigating number of particles
generated on the deposited thin film employing vapor phase
deposition apparatus 100 according to the present embodiment under
a condition of changing the temperature by changing electric power
to the valve 159 was conducted. In order to investigate an
influence of the temperature of the valve 159 on the generation of
the particles, the temperature presets of the respective regions in
the piping unit 120 except the valve 159 were presented as the
Example 1 shown in Table 3, and as a standard condition, the
temperatures of the second piping 114, the first piping 116 and the
valve 159 were set to be identical. Further, the process for
manufacturing the thin film was that described in the present
embodiment.
[0086] Results of the experiments conducted by utilizing TEMAZ are
shown in FIG. 6.
[0087] As shown in FIG. 6, in the range of the temperature of the
valve 159 of from 80 degree C. to 100 degree C., the number of the
particles in the metal compound could be reduced to a level of not
higher than 300 particles/wafer (200 mm wafer) (that is, 0.95
particle/1 cm.sup.2), which is a reference value that can
preferably be used as the high dielectric constant film.
[0088] It is also considered in the conventional apparatus having
the configuration as described in Japanese Patent Laid-Open No.
2000-282,242 that the temperatures of the whole piping unit
including valve are adjusted to be higher in view of the
temperature of the valve to similarly provide an inhibition of the
condensation of the source gas. However, in such case, the
temperature in the piping easily becomes too high, so that the
source gas may be decomposed within the pipings, thereby providing
a possible cause for the particle generation.
[0089] On the contrary, in the apparatus of the present embodiment,
the generation of the particles is inhibited as described in the
following description.
[0090] The vapor phase deposition apparatus 100 according to the
present embodiment is a type of a vapor phase deposition apparatus
100 for forming a thin film as described above, and comprises a
chamber 1060, a piping unit 120 for supplying a source material of
a thin film into the chamber 1060 in a gaseous condition, a
vaporizer 202 that is capable of vaporizing the source material
contained in a source material container 112 to supply the
vaporized material into the piping unit 120, and a temperature
control unit 180. The temperature control unit 180 comprises: a
first temperature control unit 174, which is composed of a heater
controller unit 172 and a tape heater 170 and is capable of
controlling the temperature of the first piping 116 in the piping
unit 120 that is directly connected to the chamber 1060; a second
temperature control unit 176, which is composed of a heater
controller unit 168 and a tape heater 166 and is capable of
controlling the temperature of the second piping 114 that is
connected to the vaporizer; and a third temperature control unit
178, which is composed of a heater controller unit 167 and a
thermostatic chamber 153 and is capable of controlling the
temperature of the valve 159.
[0091] A component having larger volume and thus being difficult to
be heated, like the valve 159, tends to be cooled. Such reduction
in temperature causes the condensation of the source material in
the cooled portion, and then the decomposition thereof is caused,
and eventually generating the particles. In the present embodiment,
larger electric power for heating is applied to the valve 159 than
the power applied to the first piping 116 and the second piping 114
to maintain the temperature of the valve 159 at the same
temperature as the temperature of the second piping 114 and the
first piping 116, thereby improving the purging efficiency. Thus,
the generation of the particles can be avoided.
[0092] More specifically, in the present embodiment, the valve 159
between the first piping 116 and the second piping 114 in the
piping unit 120 is housed within the thermostatic chamber 153
(equivalent to the tape heater) separately from the tape heater 170
and the tape heater 166 and is controlled by the heater controller
unit 167, and larger electric power for heating is applied thereto
to control the temperature of the first piping 116 at the same
temperature as the temperature of the second piping 114.
[0093] Here, the source material, which is particularly illustrated
in the example employed in the present embodiment, is characterized
in the relation ship of:
decomposition temperature (T2)-vaporization temperature (T1)<20
degree C.,
[0094] that is, there is a limitation in the value of T2, and thus
it is difficult to control the temperature of the first piping 116
at sufficient higher temperature. This is because higher
temperature of the first piping 116 than T2 provides larger
probability that the particles are generated by the decomposition
of the source gas. Further, since the vapor pressure is also lower,
it is difficult to conduct the purge after the source material is
passed, and thus it is prone to remain in the piping. The residual
source material remained in the piping may be decomposed in passage
of time, or may be released within the chamber 1060 by an
inappropriate step in the deposition process to be mixed with the
gases, thereby causing the generation of the particles.
[0095] The unpurged residual materials were remained in the valve
and the piping when the temperature of the valve 159 was lower than
80 degree C., these materials were decomposed as time passes, or
the mixing of the gases was occurred due to the release thereof
into the chamber by an inappropriate step in the deposition
process, to generate the particles. Further, the source materials
were decomposed in very short time within the piping when the
temperature of the valve 159 was higher than 100 degree C., and
thus the decomposed materials became the particles.
[0096] The use of the vapor phase deposition apparatus 100
according to the present embodiment allows to suitably control the
temperature within the piping unit 120 so as not to decrease the
temperature of the portion of the valve 159, and the temperature
control for the piping unit 120 can be conducted by utilizing such
procedure in accordance with the characteristics of the deposition
source material, thereby inhibiting the generation of the particles
and providing the stable deposition of the thin film.
Second Embodiment
[0097] An experiment for investigating number of particles
generated on the deposited thin film employing vapor phase
deposition apparatus 100 described in the first embodiment and
employing various types of amino acids including TEMAZ as the first
source material, under a condition of changing the temperature by
changing electric power to the valve 159, was conducted. The
temperature presets of the respective regions in the piping unit
120 except the temperature of the valve 159 were presented as shown
in Table 4. Further, the process for manufacturing the thin film
was that described in the first embodiment.
4 TABLE 4 PIPING UNIT 120 VAPORIZER (EXCLUDING VALVE 159) 202 TEMAZ
80 degree C. to 60 degree C. to 100 degree C. 85 degree C. TDEAZ 85
degree C. to 65 degree C. to 105 degree C. 90 degree C. TEMAH 90
degree C. to 70 degree C. to 110 degree C. 95 degree C. TDEAH 100
degree C. to 80 degree C. to 120 degree C. 105 degree C.
[0098] Results of the experiments conducted for the amino acids
including TEMAZ is shown in FIG. 7.
[0099] As shown in FIG. 7, in the case of utilizing TEMAZ, the
number of the particles in the metal compound could be reduced to a
level of not higher than 300 particles/wafer (200 mm wafer) (that
is, 0.95 particle/1 cm.sup.2), which is a reference value that can
preferably be used as the high dielectric constant film, in the
range of the temperature of the valve 159 of from 80 degree C. to
100 degree C.
[0100] Further, in the case of utilizing TDEAZ, the number of the
particles in the metal compound could be reduced to a level of not
higher than 300 particles/wafer (200 mm wafer) (that is, 0.95
particle/1 cm.sup.2), which is a reference value that can
preferably be used as the high dielectric constant film, in the
range of the temperature of the valve 159 of from 85 degree C. to
105 degree C.
[0101] Further, in the case of utilizing TEMAH, the number of the
particles in the thin film could be reduced to a level of not
higher than 300 particles/wafer (200 mm wafer) (that is, 0.95
particle/1 cm.sup.2), which is a reference value that can
preferably be used as the high dielectric constant film, in the
range of the temperature of the valve 159 of from 90 degree C. to
110 degree C.
[0102] Further, in the case of utilizing TDEAH, the number of the
particles in the thin film could be reduced to a level of not
higher than 300 particles/wafer (200 mm wafer) (that is, 0.95
particle/1 cm.sup.2), which is a reference value that can
preferably be used as the high dielectric constant film, in the
range of the temperature of the valve 159 of from 100 degree C. to
120 degree C.
[0103] As such, a precise temperature control in the valve 159 is
conducted for the source material having the relationship of the
vaporization temperature and decomposition temperature, in which
the temperature difference therebetween is within 20 degree C., and
the temperature of the piping unit 120 is preset to be equal to or
higher than the vaporization temperature (T1) and equal to or less
than a temperature that is the decomposition temperature (T2) plus
20 degree C., and therefore the temperature control of the piping
unit 120 can be conducted in accordance with the characteristics of
the source material, thereby inhibiting the generation of the
particles. This provides the stable deposition of the thin
film.
Third Embodiment
[0104] FIG. 4 schematically illustrates a status of the vapor phase
deposition apparatus 200 according to the present embodiment during
the introduction of the first source gas.
[0105] The vapor phase deposition apparatus 200 in the present
embodiment has substantially the same configuration as the
configuration of the vapor phase deposition apparatus 100 according
to the first embodiment, except that the temperature of the valve
159 between the second piping 114 and the first piping 116 is
controlled by the same heater that is also used for controlling the
temperature of the first piping 116.
[0106] The vapor phase deposition apparatus 200 comprises, in the
piping unit 120 for supplying the first source material: a first
temperature control unit 184, which is composed of a heater
controller unit 172 and a tape heater 170 and is capable of
controlling the temperature of the first piping 116 and the valve
159; and a second temperature control unit 186, which is composed
of a heater controller unit 168 and a tape heater 166 and is
capable of controlling the temperature of the second piping
114.
[0107] Values of electric power presets in the case of employing
the vapor phase deposition apparatus 200 according to the present
embodiment and employing TEMAZ as the first source material for
respective temperature control units (that is, the first
temperature control unit 184 and the second temperature control
unit 186) and the corresponding measured temperatures are shown in
Table 5.
5 TABLE 5 FIRST PIPING 116 and SECOND VAPORIZER VALVE 159 PIPING
114 202 EXAMPLE 1 POWER 14 8 -- PRESET (W) MEASURED 100 80 80
TEMPERATURE (degree C.) EXAMPLE 2 POWER 13 8 -- PRESET (W) MEASURED
90 85 80 TEMPERATURE (degree C.)
[0108] Similarly as in the first embodiment, the preset
temperatures may more preferably form a temperature gradient that
gradually elevates from the vaporizer 202 to the first piping 116.
This is because, even though there is an insufficiently heated
portion in the respective parts (first piping 116, valve 159 and
second piping 114), the condensation of the source material in the
insufficiently heated portion can be inhibited by setting higher
temperature than the vaporizer 202.
[0109] Further, it is desirable to control the first piping 116 to
maintain the temperature of the first piping 116 that is
sufficiently high but not higher than the decomposition temperature
of the source material, since the purge in the pipings can be
easily carried out at such temperature, and further, even if the
source material is remained within the piping, the generation of
the particles due to the decomposition of the residual source
material by the passage of time or due to the mixing of the gases
released within the chamber 1060 by an inappropriate step in the
deposition process can be avoided, and for example, Example 2 is a
more preferable in Table 5.
[0110] In the vapor phase deposition apparatus 200 according to the
present embodiment, the same tape heater 170 is employed to control
the temperatures of the first piping 116 and the valve 159 to
maintain the temperatures thereof at higher temperature than that
of the second piping 114. The decrease of the temperature of the
valve 159 in the piping unit 120 is inhibited and the condensation
and the decomposition of the source gas at the valve 159 in the
piping unit 120 is inhibited to prevent the generation of the
particles, and thereby providing stable deposition of the thin
film.
Fourth Embodiment
[0111] The present embodiment illustrates an example of applying
the present invention to a metal oxide semiconductor field effect
transistor (MOSFET) . The MOSFET according to the present
embodiment has a structure shown in FIG. 9. The transistor shown in
FIG. 9 comprises, on a silicon substrate 400, a gate electrode,
which includes a multi-layered body of a gate insulating film
composed of a multi-layered body of a silicon oxynitride film 402
and a thin film 404 on the silicon oxynitride film 402, and a gate
electrode 406 composed of polysilicon. Side walls 410 composed of a
silicon oxide film are formed on side faces of the gate electrode.
A source and drain region 412 containing an impurity diffused
therein are formed on the face of the silicon substrate 400 in both
sides of the gate electrode.
[0112] The thin film 404 has a chemical composition represented by
HfO.sub.xc.sub.yN.sub.z(where x, y and z are selected to satisfy
0<x,0.1.ltoreq.y.ltoreq.1.25, 0.01.ltoreq.z and x+y+z=2).
Penetration of an impurity in the gate electrode to the silicon
substrate can be effectively inhibited by employing such film.
[0113] Preferable source gas for the metal compound deposition may
include Hf(N(C.sub.2H.sub.5)2).sub.4, Hf(N(CH.sub.3).sub.2).sub.4,
and the like. Penetration of an impurity can be more effectively
inhibited by employing such compound.
[0114] A manufacturing process for the transistor shown in FIG. 9
will be described in reference with FIGS. 10A to 10D and FIGS. 11E
and 11F. In the beginning, as shown in FIG. 10A, a silicon
substrate 400 that surface is cleaned by using a predetermined
liquid chemical solution is prepared. Then, as shown in FIG. 10B, a
silicon oxynitride film 402 is formed on a main surface of the
silicon substrate 400 using a chemical vapor deposition (CVD)
technique. Subsequently, as shown in FIG. 10C, a thin film 404 is
formed using an atomic layer deposition (ALD) technique.
[0115] Among the deposition gases employing in this deposition
process, a metal compound represented by a general formula of Hf
(NRR').sub.4 can be employed for a metal source gas (where R and R'
are same or different hydrocarbon group(s), and preferably linear
or branched alkyl group). R and R' may preferably be alkyl group
having 6 or less carbons/carbon, and more specifically, methyl
group, ethyl group, propyl group, tertiary butyl group or the like
may be employed.
[0116] On the other hand, typical oxidizing gas employed for
depositing the thin film 404 includes oxygen or a chemical compound
containing oxygen. More specifically, the typical compounds may be
NO, NO.sub.2, N.sub.2O, H.sub.2O, O.sub.2, O.sub.3 and the like.
Among these compounds, NO, NO.sub.2 and N.sub.2O are preferable,
and a gaseous mixture of NO and NO.sub.2 and a gaseous mixture of
NO and O.sub.3, which represent combinations of nitriding gas and
oxidizing gas, are more preferable. Stable deposition of the
capacitior film having better film quality can be obtained by
selecting such compounds. Further, NO, N.sub.2O and NO.sub.2 are
easier to be removed from the deposition apparatus by purging,
thereby improving the manufacturing efficiency.
[0117] Here, the deposition process for the thin film 404 utilizes
any one of the vapor phase deposition apparatus described in the
first to the third embodiments. Further, the method for forming the
thin film 404 also utilizes any one of the methods for forming the
thin film described in the first to the third embodiments.
[0118] The supply of the deposition gas is conducted as follows,
for example. Firstly, Hf(N(CH.sub.3)(C.sub.2H.sub.5)).sub.4 is
supplied as a source material in a chamber of an ALD apparatus to
cause a chemical reaction on a surface of a lower electrode thin
film, so that one atomic layer is deposited thereon. Next the
supply of Hf(N(CH.sub.3)(C.sub.2H.su- b.5))4 is stopped, and then,
an inert gas, typical example of which include N.sub.2, Ar or the
like, is introduced into the chamber as a purge gas to purge or
flush the excess amount of unreacted
Hf(N(CH.sub.3)(C.sub.2H.sub.5)).sub.4 out.
[0119] Then, NO gas is supplied therein to remove functional group
that terminates Hf deposited on the substrate. Then, the supply of
NO gas is stopped, and an inert gas, typical example of which
include N.sub.2, Ar or the like, is introduced therein as a purge
gas to purge or flush unreacted NO and/or byproducts after
reaction, and then the supply of the purge gas is stopped.
[0120] As described above, a desired number of the sequential
process cycle consisting of the supply of
Hf(N(CH.sub.3)(C.sub.2H.sub.5)).sub.4, the first purge, the supply
of NO and the second purge are repeated to obtain the thin film 404
consisting of HfO.sub.xC.sub.yN.sub.z having a film thickness of 5
to 15 nm (where x, y and z are selected to satisfy 0<x,
0.1.ltoreq.y.ltoreq.1.25, 0.01.ltoreq.z and x+y+z=2).
[0121] Thereafter, a gate electrode film 406 is formed on the thin
film 404, as shown in FIG. 10D. It is preferable to employ
polycrystalline silicon for the gate electrode film 406, and
otherwise, a metal electrode such as SiGe, TiN, WN, Ni and the like
can also be employed.
[0122] Subsequently, as shown in FIG. 1E, the silicon nitride 402,
the thin film 404 and the gate electrode film 406 are etched to
form a predetermined shape, thereby obtaining a gate electrode.
Thereafter, side walls 410 are formed onto side faces of the gate
electrode and an impurity is introduced into the gate electrode and
the face of the silicon substrate 400 in both sides thereof. As
described above, the MOSFET shown in FIG. 11F is manufactured.
[0123] Since the gate insulating film in the MOSFET according to
the present embodiment includes the thin film 404, which is formed
by employing the vapor phase deposition apparatus described in any
of the first to the third embodiments and employing the process for
forming the thin film described in any of the first to the third
embodiments, the penetration of an impurity contained in the gate
electrode film 406 through the gate insulating film into the
silicon substrate 400 can be effectively prevented. Therefore, the
transistors having, higher reliability can be obtained.
Fifth Embodiment
[0124] The present embodiment relates to a cylinder type
metal-insulator-metal (MIM) capacitance device. FIG. 12 is a
diagram showing a schematic configuration of a capacitance device
according to the present embodiment. A cylinder type MIM
capacitance device is provided on a transistor having a gate
electrode 323 and a source drain region 324 through a capacitor
contact 331.
[0125] The capacitance device has a multi-layered structure
comprising a lower electrode (first electrode) 340, a capacitor
film 342, an upper electrode 344 and a tungsten film 346, which are
formed in this order and are patterned to a predetermined shape.
Further, a bit line 329 is formed on the transistor through a cell
contact 328.
[0126] Although the bit line 329 and the capacitor contact 331 are
illustrated in the same cross-sectional view in FIG. 12, the
illustration is made for helping to understand the whole structure
thereof, and in reality, these do not intersect. More specifically,
the bit line 329 is disposed within a gap in a region where the
capacitor contact 331 is provided.
[0127] The deposition source materials for depositing the capacitor
film 342 may include Zr(N(C.sub.2H.sub.5).sub.2).sub.4,
Zr(N(CH.sub.3).sub.2).sub.4, Zr(N(CH.sub.3)(C.sub.2H.sub.5)).sub.4
and the like. Selection of such chemical compounds provides a film
having a flat and smooth surface and a prevention of a
contamination of particles in the thin film. As a result, the
capacitor film providing lower leakage current and having better
film quality can be obtained.
[0128] Typical oxidizing gas employed for depositing the capacitor
film 342 includes oxygen or a chemical compound containing oxygen.
More specifically, the typical compounds may be NO, NO.sub.2,
N.sub.2O, H.sub.2O, O.sub.2, O.sub.3 and the like. Among these
compounds, NO, NO.sub.2 and N.sub.2O are preferable, and a gaseous
mixture of NO and NO.sub.2 and a gaseous mixture of NO and O.sub.3,
which represent combinations of nitriding gas and oxidizing gas,
are more preferable. Stable deposition of the capacitor film having
better film quality can be obtained by selecting such combination
of gases.
[0129] Here, for the deposition process for the capacitor film 342
employing the above-described source materials, any one of the
vapor phase deposition apparatus described in the first to the
third embodiments is employed. Further, the method for forming the
capacitor film 342 also utilizes any one of the methods for forming
the thin film described in the first to the third embodiments.
[0130] While the embodiments of the present invention have been
described above in reference to the annexed figures, it should be
understood that the disclosures above are presented for the purpose
of illustrating the present invention, and various configurations
other than the above-described configurations can also be
adopted.
[0131] For example, while the method for supplying the source
material such as TEMAZ into the chamber 1060 in the above-described
embodiment employs a down flow system, in which the shower head 108
is provided on the upper portion of the chamber 1060, another
configuration, in which the shower head 108 is provided on a side
of the chamber 1060, may alternatively be employed. Such
alternative configuration also equally provides the inhibition to
the generation and the condensation of a particle of the source gas
such as TEMAZ according to the process for forming the thin film of
the present invention, and therefore, similarly as in the
above-described process, the high dielectric constant film having
higher quality can be stably obtained.
[0132] While various types of amino acids including TEMAZ is
employed as the source gas in the above-described embodiment, for
example, other source gases having a vaporization temperature that
is closer to a decomposition temperature may alternatively be
employed. In such case, the use of the vapor phase deposition
apparatus according to the present invention allows an accurate
control of the temperature of the source material supplying piping
in accordance with characteristics of the source gas, and thus the
condensation or the decomposition of the source gas within the
source material supplying piping can be inhibited, thereby
similarly providing the thin film having improved quality.
[0133] It is apparent that the present invention is not limited to
the above embodiment, that may be modified and changed without
departing from the scope and spirit of the invention.
* * * * *