Single-crystal – oriented-crystal – and epitaxy growth processes; – Forming from vapor or gaseous state – With decomposition of a precursor
Reexamination Certificate
2001-03-12
2003-05-20
Kunemund, Robert (Department: 1765)
Single-crystal, oriented-crystal, and epitaxy growth processes;
Forming from vapor or gaseous state
With decomposition of a precursor
C117S093000, C117S102000, C117S200000, C118S715000, C118S716000
Reexamination Certificate
active
06565655
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a high vacuum apparatus, and more particularly to a high vacuum apparatus for fabricating a semiconductor device that is capable of preventing contaminant particles from generating due to cooling and condensing of reactive gas. The present invention also relates to a method for growing an epitaxial layer with less contaminant particles.
2. Description of the Background Art
As semiconductor devices get to have a higher function and become more highly integrated, contaminant degree due to contaminant particles directly affects the yield of a product.
Thus, efforts are increasingly made with importance to analyze the cause of generation of the contaminant particles and reduce the contaminant particles. Such efforts are important for the clean room environment and a gas convey system of semiconductor process equipment, and more importantly, it is more critical for equipment for performing processes since more contaminant particles are generated especially therein.
In an effort to solve the problems, according to an experiment on the cause of contaminant particles within a high vacuum reactive chamber for forming an epitaxial thin film by the present inventors, they noted that the position relationship between a gas inlet and a gas outlet has much influence on the generation of contaminant particles.
FIGS. 1A through 1C
are sectional views of a high vacuum reactive chamber in accordance with a conventional art.
FIG. 1A
is a sectional view of a high vacuum reactive chamber in accordance with a first embodiment of a conventional art.
With reference to
FIG. 1
, there is shown a reactive chamber
100
. A gas inlet
106
is installed at one wall side of the reactive chamber
100
, and a gas outlet is formed at the bottom of the reactive chamber
100
. The gas outlet is connected with a vacuum pump.
A suscepter
102
is installed in the reactive chamber
100
, on which a semiconductor substrate
104
is mounted.
In the apparatus of
FIG. 1
, when an epitaxial thin film is deposited at the upper surface of the semiconductor substrate
104
, the reactive gas supplied into the reactive chamber
100
through the gas inlet
106
forms a gas flowing
100
a
in the direction parallel to the upper surface of the substrate
104
at the upper portion of the substrate
104
, and a discharge gas is discharged through the gas outlet provided at the lower center portion of the reactive chamber
100
to communicate with the vacuum pump (not shown).
FIG. 1B
illustrates an inspection result according to observation of contaminant particles of the semiconductor substrate processed in the reactive chamber of FIG.
1
A.
With reference to
FIG. 1B
, there are observed short band-shaped particles
105
in the same direction as the gas flowing
100
a
on the substrate
104
.
FIG. 1C
illustrates the result of measurement of the number of contaminant particles for the semiconductor substrate of FIG.
1
B.
As shown in
FIG. 1C
, the number of contaminant particles is shown by regions. It is noted that the more distance from where the substrate
104
initially contacts the gas flowing
100
a
becomes, the more the contaminant particles. That is, the region
107
a
includes the most contaminant particles in number, the region
107
b
has the middle number of contaminant particles, and the region
107
c
has the least contaminant particles.
In other words, the region
107
c
nearest to the gas inlet has the lowest contamination level while the region
107
a
farthest to the gas inlet has the highest contamination level. The reason for this is judged that the reactive gas is dispersed from the gas inlet, collides with the inner wall of the opposite reactive chamber, cooled and condensed to generate the contaminant particles.
FIGS. 2A through 2C
are diagrams for explaining generation of contaminant particles in the high vacuum reactive chamber in accordance with the second embodiment of the conventional art.
FIG. 2
is a sectional view of a high vacuum reactive chamber
200
in accordance with a second embodiment of the conventional art.
With reference to
FIG. 2A
, a reactive chamber
200
is shown. A gas inlet
206
is formed at the ceiling of the reactive chamber
200
and a gas outlet is installed at the bottom of the reactive chamber
200
, to which a vacuum pump is connected.
A suscepter
202
is installed at the central portion in the chamber
200
, on which a semiconductor substrate
204
is mounted.
When an epitaxial layer is deposited at the upper surface of the semiconductor substrate
204
by using the apparatus of
FIG. 2A
, the reactive gas is supplied through the gas inlet
206
installed at the center of the ceiling of the chamber
200
to the reactive chamber
200
, forming the gas flowing
200
a
in the direction in which the gas collides with the center of the semiconductor substrate
204
. A discharge gas is discharged through the gas outlet provided at the center of the bottom of the reactive chamber
200
to communicate with a vacuum pump (not shown).
FIG. 2B
is a diagram showing a result of inspection with naked eye of the contaminant particles of the semiconductor substrate which has undergone the processes in the reactive chamber of FIG.
2
A.
With reference to
FIG. 2B
, as the gas flowing
200
a
collides with the substrate
204
, a collision form of pattern
205
was observed around the center of the substrate
204
.
FIG. 2C
is a diagram showing a result of measurement of the number of the contaminant particles of the semiconductor substrate of FIG.
2
B.
FIG. 2C
also shows the number of contaminant particles by regions, of which, notably, the region
207
a
where the substrate
204
first collides with the gas flowing
200
a
includes many contaminant particles, whereas less contaminant particles were observed in the region
207
b
, which is distant from the region
207
a.
This result shows somewhat different from that of
FIG. 1C
where the farther the reactive gas becomes distance from the gas inlet, the more contaminant particles are generated. The reason for this is considered that the reactive gas is heat-exchanged with the substrate
204
at the portion where the gas flowing
200
a
directly collides with the substrate
204
, cooled and condensed to generate the contaminant particles. Thus, the position where the gas flowing initially collides with inside the reactive chamber
200
is one of principal variants to generate the contaminant particles.
FIGS. 3A through 3C
are diagrams showing generation of contaminant particles in the high vacuum reactive chamber in accordance with a third embodiment of the conventional art.
FIG. 3A
is a sectional view of a high vacuum reactive chamber in accordance with the third embodiment of the conventional art.
With reference to
FIG. 3A
, there is shown a reactive chamber
300
, in which a suscepter
302
is installed. A semiconductor substrate
304
is mounted at the upper surface of the suscepter
302
.
A gas injector
305
is installed at one side spaced apart from the suscepter
302
, through which a reactive gas is injected into the reactive chamber
300
.
The supplied reactive gas first collides with the wall of the dome-shape ceiling of the reactive chamber
300
or makes a gas flow indicated by a reference numeral
300
a
due to gravity of itself.
Meanwhile, a discharge gas is discharged through a gas outlet provided at the lower center of the reactive chamber
300
, communicating with a vacuum pump (not shown).
FIG. 3B
is a result of inspection with a naked eye of the contaminant particles of the semiconductor substrate which has undergone the processes in the reactive chamber of FIG.
3
A. It is noted that a circular pattern
305
is widely observed in the portion where the gas flowing
300
a
contacts the substrate
304
.
FIG. 3C
is a diagram of a result of measurement of the number of the contaminant particles of the semiconductor substrate of FIG.
3
B. Like the result of
FIG. 1C
, the farther the substrate
304
first contacts the g
Hwang Chul-Ju
Kim Sung-Ryul
Park Jae-Kyun
Jusung Engineering Co. Ltd.
Kunemund Robert
Ostrolenk Faber Gerb & Soffen, LLP
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