Chemical vapor deposition apparatus with a heat radiation structure

A chemical vapor deposition (CVD) apparatus having a heat radiation structure. The CVD apparatus has a process chamber wherein the semiconductor substrate is located, a gas inlet for introducing a process gas into the process chamber, a manifold for supporting the process chamber and the gas inlet, and a heat radiating member provided around the gas inlet, for radiating heat transmitted from the manifold. The gas inlet has a plurality of radiation plates formed around the gas inlet and a plurality of through-holes formed in each of the radiation plates. With the gas inlet having the heat radiating structure, heat from the manifold during the deposition process is not transmitted to the gas supply line and the like. Thus the associated parts are not corroded or deformed.

BACKGROUND OF THE INVENTION 
1. Field of Invention 
The present invention relates to a chemical vapor deposition apparatus for 
depositing a thin film on a semiconductor substrate, and more 
particularly, this invention relates to a chemical vapor deposition (CVD) 
apparatus having a gas inlet with heat radiating plates to present heat 
from being transmitted from the gas inlet to a gas supply line. 
2. Description of the Related Art 
FIG. 1A is a cross-sectional representation of a vertical furnace of a 
conventional chemical vapor deposition machine which is used to deposit a 
thin film on a semiconductor substrate. The CVD machine has a vertical 
furnace which consists of an outer tube 110 and an inner tube 111 disposed 
within the outer tube 110. The vertical furnace is fixed by a manifold 130 
which is made of a metal and provided to isolate the tubes 110 and 111 
from the atmosphere. On both sides of the vertical furnace, a heater 120 
is provided to keep the internal temperature of the furnace constant. 
FIG. 1B is an enlarged view of portion "A" of the manifold shown in FIG. 
1A. As shown in FIG. 1B, a gas supply line 160 and a gas injector 150 are 
connected to each other through a gas inlet 140, which is fixed to the 
manifold 130, so as to introduce a process gas into the vertical furnace 
serving as a process chamber. The process gas is supplied through the gas 
supply line 160. Corrosion of the gas inlet 140 exerts a negative 
influence on the deposition process. The gas injector 150 and the gas 
supply line 160 communicate with respective ends of the gas inlet 140. 
Reference numerals 161 and 170 are a nozzle and an O-ring, respectively. 
In the conventional CVD apparatus with the above described construction, 
the furnace is heated by the heater 120 and is maintained at a high 
temperature during the deposition process. The manifold 130 is heated to a 
high temperature by the heated furnace. The high temperature of the 
manifold 130 is transmitted to the gas inlet 140 and the gas supply line 
160, which are coupled to the manifold 130, causing corrosion of the 
manifold and associated parts, and deformation of the O-ring 170. It 
becomes difficult to dissolve the corrosion and reassemble the corroded 
parts. In addition, the degradation of the O-ring 170 lowers its sealing 
performance. 
Also, the corrosion of the associated parts causes particles, which may, 
together with the gas, flow into the furnace. Such particles contaminate 
the inside of the furnace, whereby defects are generated on a 
semiconductor substrate during the deposition process. 
To solve such problems, heat radiating techniques have been proposed. One 
technique is to extend the length of the gas inlet. With this technique, 
however, the equipment size is increased and the radiation effect is 
insufficient. 
SUMMARY OF THE INVENTION 
It is therefore an object of the present invention to provide a chemical 
vapor deposition apparatus having a gas inlet with heat radiating plates 
to prevent the transmission of heat from the gas inlet to a gas supply 
line. 
It is another object of the present invention to provide a chemical vapor 
deposition apparatus with a heat radiation structure which can prevent the 
gas inlet from being deformed and/or corroded due to the large amount of 
heat generated during the deposition process. 
It is a further object of the present invention to provide a chemical vapor 
deposition apparatus with a heat radiation structure which is smaller in 
size but which has superior radiation effects. 
According to an aspect of the present invention, a chemical vapor 
deposition apparatus for depositing a thin film on a semiconductor 
substrate, comprises a process chamber wherein the semiconductor substrate 
is located; a gas inlet for introducing a process gas into the process 
chamber; a manifold for supporting the process chamber and the gas inlet; 
and heat radiating means provided around the gas inlet for radiating heat 
transmitted from the manifold. The process chamber comprises a vertical 
furnace having a first outer tube and a second tube formed inside the 
first tube. The heat radiating means comprises a plurality of radiation 
plates formed around the gas inlet. With the heat radiating means, the 
heat transmitted from the manifold during the deposition process can 
radiate through the radiation plates. 
Thus, the CVD apparatus according to this invention can prevent the gas 
inlet from being deformed and/or corroded due to the high heat which is 
transmitted from the manifold.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to FIGS. 2A, 2B and 3, a novel CVD apparatus in accordance with 
the present invention comprises a gas inlet 20 for introducing a process 
gas through a gas injector 30 into a process chamber which serves as a 
vertical furnace. A manifold 10 supports the process chamber and the gas 
inlet 20. Heat radiating means are provided around the gas inlet 20, for 
radiating heat transmitted from the manifold 10. The process chamber has a 
first outer tube and a second tube formed inside the first tube, similar 
to that of FIG. 1A. 
Referring specifically to FIGS. 2A and 2B, the gas inlet 20 has heat 
radiating means, which is composed of a plurality of radiation plates 21, 
around the gas inlet 20. The plates 21 may be substantially formed around 
the gas inlet 20 in a single body. Each of the plates 21 has a plurality 
of through-holes 21a formed therein, such that the heat radiation effect 
can be improved. The diameter "D" of each of the through-holes 21a is 
larger that the thickness "T" of each of the radiation plates 21. 
FIG. 3 shows a portion of the CVD apparatus with which the gas inlet 20 of 
this embodiment is implemented. In FIG. 3, a gas injector 30 inside the 
process chamber is combined with one end of the gas inlet 20, which is 
connected to the gas injector through the manifold 10. A nozzle 50 and a 
gas supply line 40 are connected to the other end of the gas inlet 20. 
Numeral 60 is an O-ring for maintaining a solid sealing state between the 
gas inlet 20 and the nozzle 50. 
As described above, a CVD apparatus according to the present invention has 
a gas inlet which radiates the heat transmitted from a manifold during the 
deposition process, so that corrosion and deformation of the manifold and 
its associated parts are prevented. 
Additionally, since the through-holes 21a on each radiation plate 21 of the 
gas inlet 20 play an important role in improving the heat radiation 
effect, the CVD apparatus itself has an improved radiation effect. 
Although preferred embodiments of the present invention have been described 
in detail hereinabove, it should be clearly understood that many 
variations and/or modifications of the basic inventive concepts herein 
taught, which may appear to those skilled in the art, will still fall 
within the spirit and scope of the present invention as defined in the 
appended claims and their equivalents.