Coating apparatus – Gas or vapor deposition
Reexamination Certificate
2001-07-12
2003-02-04
Lund, Jeffrie R. (Department: 1763)
Coating apparatus
Gas or vapor deposition
C118S050000, C156S345290, C156S345330, C156S345340, C417S423400
Reexamination Certificate
active
06514348
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a substrate processing apparatus for processing a substrate such as a semiconductor substrate, and more particularly to a substrate processing apparatus for processing a semiconductor substrate for formation of a thin film, polishing, or the like in a chamber evacuated by a vacuum pump.
2. Description of the Related Art
Generally, when a substrate is processed at a pressure lower than the atmospheric pressure (hereinafter referred to as “vacuum”), the substrate is introduced into a vacuum chamber evacuated by a vacuum pump, and a process, such as formation of a thin film, plating, or polishing, is then carried out in the vacuum chamber. Various methods are known for forming a thin film on the surface of a substrate. These methods include physical vapor deposition (PVD) such as sputtering and ion plating, and chemical vapor deposition (CVD) utilizing vacuum evaporation or thermal reaction or plasma excitation under a low pressure. In addition to the thin film deposition, various other methods of processing a substrate at a low pressure, such as surface processing with dry etching, pattern exposure, resist processing, cleaning, drying, annealing, ion implantation, inspection, and measurement.
FIG. 5
is a schematic view showing an example of the whole structure of a conventional substrate processing apparatus, which is a film deposition apparatus for forming a thin film of a high dielectric material or a ferroelectric material, such as barium titanate, strontium titanate, or the like, through the CVD process. As shown in
FIG. 5
, in this substrate processing apparatus (film deposition apparatus), a hermetically sealed vacuum chamber (deposition chamber)
110
is provided downstream of a vaporizer (a gas generator)
100
for vaporizing a liquid raw material. A shutoff valve
112
and a conductance valve
113
are disposed downstream of a suction port
111
provided in the deposition chamber
110
. Further, a turbo-molecular pump
120
and a roughing vacuum pump
120
a
as vacuum pumps are disposed downstream of the conductance valve
113
. A substrate holding section (susceptor)
114
for holding a substrate W is provided in the deposition chamber
110
. A gas ejection head (shower head)
115
as a gas ejection portion for ejecting a deposition gas toward the substrate W is provided on the upper portion of the deposition chamber
110
. An oxidizing gas pipe
130
for supplying an oxidizing gas such as oxygen is connected to the deposition chamber
110
.
In such a substrate processing apparatus, a substrate W to be processed is placed on the substrate holding section
114
with the use of a robot hand or the like, and the deposition chamber
110
is evacuated by the vacuum pumps
120
,
120
a
. Then, a lifting/lowering mechanism (not shown) connected to the substrate holding section
114
is driven to lift the substrate holding section
114
to a position for film deposition. A raw material gas mixed with an oxidizing gas is ejected from nozzle holes formed in the gas ejection head
115
toward the substrate W while the substrate W is kept at a predetermined temperature by a temperature adjustment mechanism (not shown). The ejected gases of the raw material gas and the reactive gas are reacted with each other on the surface of the substrate W to form a film thereon. The reacted gas is discharged through the suction port
111
by the vacuum pumps
120
,
120
a
. In some cases, the film deposition is performed while the substrate W on the substrate holding section
114
is being rotated by a rotation mechanism (not shown).
The pressure in the deposition chamber
110
is controlled by adjusting the degree of opening of the shutoff valve
112
and the conductance valve
113
connected to the suction port
111
, and by adjusting the amount of gas ejected from the gas ejection head
115
. When one of the vacuum pumps
120
,
120
a
is replaced with new one, the shutoff valve
112
is closed to keep the interior of the deposition chamber
110
under vacuum. On the other hand, when a plurality of vacuum pumps
120
,
120
a
are disposed in the system, a shutoff valve disposed upstream of a vacuum pump that is not operated is closed.
In order to efficiently process the substrate, it is necessary to optimize the positional relationship between the substrate and the components in the apparatus or between the substrate and a vacuum pump (vacuum evacuation section). Particularly, this positional relationship should preferably be designed such that the gas introduced from the gas ejection portion is evenly ejected onto the whole surface of the substrate.
Further, in order to improve productivity of processing a substrate and to increase the substrate processing level (fineness), it is necessary to improve the responsiveness in the pressure control in the case where the pressure in the chamber is controlled from an initial pressure to a predetermined pressure. Specifically, it is necessary to dispose the gas ejection portion at a proper position relative to the surface of the substrate for speedily introducing and discharging the gas and improving the controllability of the pressure around the surface of the substrate.
Further, the vacuum pump (vacuum evacuation section) such as a turbo-molecular pump, the shutoff valve and the conductance valve for adjusting the pressure in the chamber, the gas ejection portion, and the like are provided in the conventional substrate processing apparatus, independently of each other. Therefore, spaces for each of these components are required, thereby increasing the size of the apparatus and the vacuum chamber.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above drawbacks. It is therefore an object of the present invention to provide a substrate processing apparatus which can optimize a positional relationship between a substrate to be processed and a gas ejection portion or between the substrate and a vacuum evacuation section to improve the responsiveness in a pressure control around the surface of the substrate, and can be downsized.
In order to attain the above object, according to an aspect of the present invention, there is provided a substrate processing apparatus for processing a substrate introduced into a chamber under a low pressure, the substrate processing apparatus comprising: a vacuum pump for evacuating the chamber, the vacuum pump being disposed in the vicinity of the chamber; and a gas ejection portion provided in the vacuum pump for ejecting a gas toward the substrate.
According to another aspect of the present invention, there is provided a substrate processing apparatus for processing a substrate introduced into a chamber under a low pressure, the substrate processing apparatus comprising: a vacuum pump for evacuating the chamber, the vacuum pump being disposed inside of the chamber; and a gas ejection portion provided in the vacuum pump for ejecting a gas toward the substrate.
With this structure, a vacuum pump for evacuating the chamber is provided integrally with a gas ejection portion for ejecting a gas toward the substrate. Accordingly, both of evacuation of a gas from the surface of the substrate and ejection of a gas onto the surface of the substrate can directly be performed, so that the pressure around the surface of the substrate can speedily be adjusted. Therefore, the productivity and quality of processing a substrate can be improved.
When the gas ejection portion in the vacuum pump is provided on a suction side of the vacuum pump, the gas can efficiently be introduced into the chamber while the exhaust capacity of the vacuum pump is sufficiently maintained. Particularly, in the case of a turbo-molecular pump having a rotating exhaust section and a stationary exhaust section which are concentrically provided, no exhaust capacity can be obtained on a rotating shaft of a rotor, i.e., at positions inside of the inner circumferential portion of rotary vanes. Therefore, when the gas ejection portion and a path necess
Armstrong Westerman & Hattori, LLP
Ebara Corporation
Lund Jeffrie R.
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