Coating apparatus – Gas or vapor deposition
Reexamination Certificate
1999-05-18
2001-02-06
Lund, Jeffrie R. (Department: 1763)
Coating apparatus
Gas or vapor deposition
C204S298150
Reexamination Certificate
active
06183563
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for depositing thin films on a semiconductor wafer.
2. Description of the Related Art
Referring to
FIGS. 1 and 2
, a conventional thin film deposition apparatus comprises a reactor
1
, first and second pipes
2
and
3
through which first and second reaction gases are injected into the reactor
1
, and an exhaust pipe
4
for exhausting the reaction gases from the reactor
1
. Also, first and second valves
5
and
6
which are opened or closed by a controller (not shown) are connected to the fist and second pipes
2
and
3
, respectively, and a pump
7
is installed in the exhaust pipe
4
.
In the apparatus with the above structure, the controller closes the second valve
6
and opens the first valve
5
, the first reaction gas is provided through the first valve
5
to the reactor
1
, and then exhausted through the exhaust pipe
4
and the pump
7
. Then, the controller closes the first valve
5
and opens the second valve
6
, the second reaction gas is provided through the second valve
6
to the reactor
1
, and then exhausted through the exhaust pipe
4
and the pump
7
.
However, during a thin film deposition step, the reaction gases provided to the reactor are deposited over the entire inner wall of the reactor exposed to the reaction gases in addition to the wafer. Thus, a cleaning step for cleaning the inner wall of the reactor must be performed periodically.
Also, because the exhaust pipe
4
is installed at only one side of the reactor
1
, the distribution of the reaction gases in the reactor
1
, that is, between a part near the exhaust pipe
4
and another part far away from the exhaust pipe
4
, is different. Such difference in distribution of the reaction gases in the reactor causes uneven distribution of the reaction gases on the wafer, thereby interfering with the laminar flow of the reaction gases over the wafer.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an apparatus for depositing thin films on a semiconductor wafer, in which the area of a part of a reactor exposed to reaction gases is reduced, making a cleaning cycle longer, and a laminar flow of the reaction gases can be ensured over the entire wafer.
To achieve the object of the present invention, there is provided an apparatus for depositing thin films on a semiconductor wafer, comprising: a reactor block receiving a semiconductor wafer; a shower head plate covering the reactor block to maintain the internal pressure of the reactor block at a predetermined level; a reaction gas supply for supplying reaction gases, the reaction gas supply connected to the shower head plate; an inert gas supply for supplying an inert gas, the inert gas supply connected to the shower head plate; an exhaust portion for exhausting the gases out of the reactor block, the exhaust portion connected to the reactor block; and a diffusion plate having a plurality of passages connected to the source of inert gas supply, a plurality of nozzles connected to the passages, the inert gas sprayed through the nozzles lowering a wall of inert gas along the inner wall of the reactor block, and a plurality of spray holes, the reaction gases spread over the wafer through the spray holes, the diffusion plate installed in the shower head plate.
Preferably, the passages are radially formed from the center of the diffusion plate, and the nozzles are formed along the outer circumference of the diffusion plate, being slanted toward the inner wall of the reactor block.
Preferably, the apparatus for depositing thin films on a semiconductor wafer further comprises a shield installed in the reactor block, such that the gas of inert gas is lowered along the inner wall of the shield.
Preferably, the apparatus for depositing thin films on a semiconductor wafer further comprises an exhaust means having an anti-flow cylinder, the wafer positioned above the anti-flow cylinder and an exhaust plate formed in the anti-flow cylinder, and the exhaust plate having at least three or more exhaust holes symmetrically arranged to be connected to the exhaust portion.
REFERENCES:
patent: 5000113 (1991-03-01), Wang et al.
patent: 5010842 (1991-04-01), Oda et al.
patent: 5522932 (1996-06-01), Wong et al.
patent: 5558717 (1996-09-01), Zhao et al.
patent: 5788747 (1998-08-01), Horiuchi et al.
patent: 5900103 (1999-05-01), Tomoyasu et al.
patent: 5906683 (1999-05-01), Chen et al.
patent: 5968276 (1999-10-01), Lei et al.
patent: 2046723 (1990-02-01), None
Choi Won-sung
Oh Kyu-un
IPS Ltd.
Lund Jeffrie R.
MacArthur Sylvia R.
Nixon & Vanderhye PC
Presta Frank P.
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