Semiconductor device manufacturing: process – Formation of semiconductive active region on any substrate – On insulating substrate or layer
Reexamination Certificate
2001-01-26
2002-05-07
Niebling, John F. (Department: 2812)
Semiconductor device manufacturing: process
Formation of semiconductive active region on any substrate
On insulating substrate or layer
C438S680000, C438S480000, C427S248100
Reexamination Certificate
active
06383897
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing a semiconductor apparatus, a semiconductor production equipment and a cleaning method thereof, more specifically relates to a method of forming a CVD thin film on a surface of a semiconductor substrate, a method of etching a semiconductor substrate, and a method of cleaning a CVD unit and a CVD reactive chamber.
When a thin film is formed by a CVD method on a semiconductor substrate, in a conventional method, a reactive gas (for example, a silane SiH4) as a gas flow
5
for film formation is supplied from outside to an upper portion of a substrate
2
placed on a suscepter
8
provided into a reactive chamber
1
of a CVD unit, shown in FIG.
5
.
Gas in supplied via a value
5
. A flow rate of the gas is controlled by a mass flow controller
7
so that pressure in the reactive chamber
1
is adjusted to be reduced to about 10 Torr while monitoring a pressure gauge
13
. Then, the substrate
2
and the suscepter
8
are heated to 650° C. by an external lamp
3
through a quartz-made wall of the reactive chamber
1
, while flowing the gas of 1 slm, so that a polycrystal silicon film is formed.
At this time, a boundary domain, which is called as a remaining region
4
where a gas does not flow, appears on a surface of the substrate
2
, and a gas for film formation is supplied from the gas flow
5
outside the remaining region
4
. The gas for film formation is diffused in the remaining region
4
and gets to the surface of the substrate. Then, the gas is decomposed so that a polycrystal silicon film is deposited.
A thickness of the remaining region
4
is influenced by the gas flow
5
. When the gas flow is not uniform, nonuniformity occurs in thickness of the remaining region
4
. As a result, the supply of a gas to the surface of the substrate
2
becomes non-uniform, a depositing speed is varied, and thus the film thickness is varied. Moreover, the supply of the gas from the gas flow
5
is usually determined by pressure division of the gas in the gas flow
5
, however under the above condition, only several percentage of the gas in the gas flow
5
is supplied to the remaining region
4
, and thus only several percentage of the gas introduced into the reactive chamber
1
is used for the deposition.
Therefore, most of the gas introduced into the reactive chamber
1
is not decomposed, and passes through a main valve
9
, a pressure adjusting conductance valve
12
and a pipe arrangement
11
so as to be discharged out of a chamber by a pump
10
. As a result, cost of forming a thin film rises.
As mentioned above, in the conventional method of forming a thin film on the semiconductor substrate by deposition, since availability of a reactive gas for film formation introduced into the CVD reactive chamber is low, there arises a problem that cost of forming a thin film rises.
BRIEF SUMMARY OF THE INVENTION
The present invention has been achieved in order to solve the above problem, and it is an object of the present invention to provide a method of producing a semiconductor apparatus and a semiconductor production equipment, which are capable of efficiently depositing a thin film on a semiconductor substrate in a reactive chamber by efficiently using a reactive gas for film formation introduced into a CVD reactive chamber when the thin film is formed by a CVD method on the semiconductor substrate, and is thus capable of reducing the cost of forming a thin film remarkably.
In addition, it is another object of the present invention to provide a method of producing a semiconductor apparatus which is capable of efficiently etching a semiconductor substrate by efficiently using an etching gas introduced into an etching chamber when a surface of the semiconductor substrate is etched in the etching chamber, and is thus capable of reducing the etching cost remarkably.
In addition, it is another object of the present invention to provide a method of cleaning a semiconductor production equipment which is capable of efficiently etching and removing a deposit by efficiently using an etching gas introduced into a semiconductor substrate processing chamber when the deposit on an inner wall surface of the semiconductor substrate processing chamber is etched and removed, and is thus capable of reducing the cleaning cost remarkably.
According to the present invention, there is provided a method of producing a semiconductor apparatus, when a thin film is formed by a CVD method on a semiconductor substrate in a CVD reactive chamber, the method comprising the steps of: providing a remaining region where a gas for film formation remains to a proximity of a surface of the semiconductor substrate; and forming a CVD thin film on the substrate by decomposing only the gas for film formation existing in the remaining region without supplying an additional gas from the outside of the remaining region to the remaining region. The step of providing the remaining region may include the steps of: introducing the semiconductor substrate into the CVD reactive chamber so as to reduce pressure in the CVD reactive chamber to not more than a predetermined value; and introducing a reactive gas into the CVD reactive chamber so as to capture the reactive gas in the CVD reactive chamber by stopping the introduction of the reactive gas when the pressure in the CVD reactive chamber obtains the predetermined value. The step of providing the remaining region may be executed with a temperature of the semiconductor substrate being set so that the CVD thin film may be not formed, and the step of forming the CVD thin film may be executed with the semiconductor substrate being heated to a temperature at which the CVD thin film is formed and without supplying an additional reactive gas from the outside of the CVD reactive chamber. The step of providing the remaining region may include reducing pressure in the CVD reactive chamber to not more than a predetermined value; introducing the semiconductor substrate into the CVD reactive chamber; introducing a reactive gas into the CVD reactive chamber so as to form a closed space to be the remaining region in the proximity of the surface of the semiconductor substrate when the pressure in the CVD reactive chamber obtains a predetermined value; and reducing an introducing flow rate of the reactive gas and at the same time introducing an inert gas into the CVD reactive chamber so as to keep the pressure in the reactive chamber at the predetermined value. The step of forming the closed space may be executed with a temperature of the semiconductor substrate being set so that the CVD thin film is not formed, and the step of forming the CVD thin film may be executed with the semiconductor substrate being heated to a temperature at which the CVD thin film is formed and without supplying an additional reactive gas from the outside of the closed space. When the semiconductor substrate is heated, a rear side of the semiconductor substrate may be heated. When the semiconductor substrate is heated, the semiconductor substrate may be moved from an area where the temperature is lower to an area where the temperature is higher.
According to the present invention, there is also provided a semiconductor production equipment, comprising: a CVD reactive chamber for inducing CVD reaction; a suscepter, for placing a semiconductor substrate, which is provided to the outside of the CVD reactive chamber; a first pipe arrangement, for introducing a reactive gas, which is provided to the outside of the CVD reactive chamber and is connected to the CVD reactive chamber; a first mass flow controller and a first valve provided in a midway of the first pipe arrangement; a second pipe arrangement, for introducing an inert gas, which is provided to the outside of the CVD reactive chamber and is connected to the CVD reactive chamber; a second mass flow controller and a second valve provided to a midway of the second pipe arrangement; a third pipe arrangement, for discharging a gas, which is provided to the outside of the CVD reactive
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Kabushiki Kaisha Toshiba
Luk Olivia T
Niebling John F.
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