Semiconductor device manufacturing: process – Introduction of conductivity modifying dopant into... – Diffusing a dopant
Reexamination Certificate
1999-10-29
2001-09-04
Christianson, Keith (Department: 2813)
Semiconductor device manufacturing: process
Introduction of conductivity modifying dopant into...
Diffusing a dopant
C438S005000
Reexamination Certificate
active
06284632
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for manufacturing a semiconductor device using a diffusion process and an annealing process.
BACKGROUND OF THE INVENTION
In general, a diffusion process is performed to form a necessary layer and an annealing process is performed to recover crystalinity and stabilize physical property. During these processes, parameters such as temperature, gas, pressure, and reaction time are controlled to form a necessary layer.
In such a diffusion process, a desirable layer is formed in accordance with the kinds of gas and the thickness of the layer is decided in accordance with the reaction time. After process conditions such as temperature and pressure, are determined, a reaction gas is introduced to form a layer or to diffuse an impurity onto a layer. Since a conventional diffusion process is performed by introducing and simultaneously exhausting a gas (impurity source gas), this leads to a very long process time and a large amount of gas can be consumed. If the process is performed by raising internal temperature of the chamber, the gas is fast dissolved and the amount of dissolved gas increases to shorten the process time. However, as a semiconductor device structure has become highly integrated requiring a shallow junction, there is a limit to use this kind of method.
Recently, a PH
3
annealing process using a sheet-fed or a vertical furnace has been used to increase the capacitance of a semiconductor device.
FIG. 1
is a flow chart showing the steps of an annealing process in accordance with a conventional method for manufacturing a semiconductor device, and
FIG. 2
is a diagram for depicting a conventional method for manufacturing a semiconductor device.
Referring to
FIGS. 1-2
, a conventional semiconductor device manufacturing process is performed by flowing a process gas. As shown in
FIG. 2
, the process gas is continuously supplied from a process gas supply apparatus
502
into a chamber
500
where a semiconductor manufacturing process is performed, and the supplied process gas is continuously exhausted from the chamber
500
through an exhausting apparatus
504
. That is, the conventional semiconductor device manufacturing process is performed with a first valve
510
installed on a supply line
506
combining the process gas supply apparatus
502
with the chamber
500
, and a second valve
512
installed on an exhausting line
508
combining the chamber
500
with the exhausting apparatus
504
being opened.
The conventional PH
3
annealing process, as shown in
FIG. 1
, includes the steps of loading a semiconductor wafer into a chamber (S
1000
), setting process conditions in the chamber (S
1005
), forming process gas flow (S
1010
), performing an annealing process (S
1015
), then, blocking process gas and purging the inside of the chamber (S
1020
), dropping internal temperature of the chamber (S
1025
), and unloading the semiconductor wafer from the chamber (S
1030
) when the annealing process is completed.
FIG. 3
is a graph showing a difference between the semiconductor device capacitance acquired through an annealing process of FIG.
1
and the capacitance without an annealing process.
Referring to
FIG. 3
, the semiconductor device capacitance “A” acquired through the PH
3
annealing process is higher than the capacitance “B” acquired without the PH
3
annealing process. A conventional PH
3
annealing process is performed at a high temperature (about 750° C.) for 3 hours and uses PH
3
of 1.5 l/min. Accordingly, this PH
3
annealing process taking a long time, results in lower yield. The time for flowing process gas practically takes 50% and more out of total time for performing a conventional PH
3
annealing process. Since the process is performed by continuously supplying the process gas, a lot of the process gas can be wasted. That is, PH
3
of 270 l is used while performing one time of the annealing process.
Consequently, a conventional a semiconductor device manufacturing process has drawbacks such as a long process time, low yield, and waste of process gas.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a method for manufacturing a semiconductor device which can reduce process time and the amount of process gas used.
According to the present invention, a method for manufacturing a semiconductor device by performing a predetermined process with respect to a predetermined object in a chamber by using process gas comprises the steps of supplying the process gas into the chamber, blocking the chamber so as to stagnate supplied process gas in the chamber, and performing the process.
According to the present invention, the step of performing the process further comprises the steps of determining whether the amount of the process gas in the chamber is less than a threshold and supplying more process gas into the chamber, if the process gas is less than the threshold, and then repeating the blocking step.
In the preferred embodiment, the process is a diffusion process or an annealing process.
A present invention process is performed by stagnating process gas in a chamber, so that a process time can be significantly reduced. As a result, it is possible to maximize yield and to substantially reduce the amount of the process gas.
REFERENCES:
patent: 5747362 (1998-05-01), Visser
patent: 5758680 (1998-06-01), Kaveh et al.
Jolly, W. “The synthesis and characterization of inorganic compounds”, Prentice Hall, pp. 524-526 (no month given), 1970.
Bae Dae-Hoon
Lee Jae-chul
Lee Se-Jin
Shin Hyun-bo
Christianson Keith
Marger & Johnson & McCollom, P.C.
Samsung Electronics Co,. Ltd.
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