CVD apparatus

Details CVD apparatus CVD apparatus

1999-09-17

2003-02-18

Goudreau, George (Department: 1763)

Cleaning and liquid contact with solids

Processes

Including application of electrical radiant or wave energy...

C216S037000, C216S067000, C216S080000, C427S569000

Reexamination Certificate

active

06520189

ABSTRACT:

BACKGROUND OF THE INVENTION
The invention relates to a photo enhanced CVD apparatus.
Many chemical vapor deposition (CVD) processes are used, such as APCVD, LP CVD, plasma CVD, thermal CVD and so forth, for depositing a film on a substrate. While these processes have their own peculiar characteristics respectively, the temperature at which each process is carried out is commonly rather high. Such high temperature process is not suitable for formation of passivation film on an aluminum electrode arrangement.
Photo enhanced CVD process has attracted the interest of artisans because it can be carried out at a comparatively low temperature. This process is based on the energy of light, namely an optical reaction is carried out. For example, in the case of photo CVD process using silane and ammonia, mercury atoms are excited by irradiation of ultraviolet light of 2,537 Å in wavelength. The process is carried out to deposit a silicon nitride film on a substrate in accordance with the following equation:
 Hg
+h
--->Hg*(“*” is a symbol for excitation)
Hg*+SiH
4
--->SiH
3
+H−+Hg(“−” is a symbol for radical)
Hg*+NH
3
--->NH
2
—+H−+Hg
yNH
2
—+x
SiH
3
--->Si
x
N
y
+zH
2
In the above equations, x, y and z are chosen appropriately.
FIG. 1
is a cross-section view showing a photo CVD apparatus which has been devised by the inventors in advance of the present invention. To facilitate the understanding of the background of the present invention, this apparatus will be briefly explained. In the figure, the apparatus comprises a reaction chamber
31
, light source chambers
39
and ultraviolet light sources
41
. Between the light source chambers
39
, a cart
35
is mounted so as to be capable of moving in the direction perpendicular to the drawing sheet. The cart is provided with heaters
37
to heat substrates mounted on the external surfaces of the cart
35
facing to the light source chambers
39
. The temperature of the substrates
33
is elevated to about 200° C. which is suitable for forming a silicon nitride film. In the reaction chamber
31
is circulated a process gas at a pressure of several Torrs. The process gas is irradiated through quartz windows
47
with light radiated from the light source
41
. A numeral
45
designates electrodes by virtue of which discharge takes place with the cart as the other electrode and undesired product deposited on the surface of the quartz windows
47
can be eliminated by sputtering.
However, with this apparatus, the thickness of deposited film depends on th spatial relationship between the light sources and the position of the substrates. Namely, the product of the CVD process may be deposited with a greater thickness at the position irradiated with stronger light. Generally speaking, the tolerable fluctuation of the thickness of the film is about 10%. Furthermore, the quartz windows
47
have to be thick to bear the differential pressure between the inside of the reaction chamber
31
and the light source chamber
39
in which cooling gas is circulated. The differential pressure may cause leakage of the cooling gas from the light source chamber
39
into the reaction chamber
31
. As an alternative, a particular cooling system may be provided for the light source chamber so the pressure in the light source chamber, and therefore the differential pressure, can be decreased. Also, when discharge between the cart
35
and the reaction chamber
31
is desired to remove unnecessary film deposited on the light window by sputtering, the discharge tends to deviate from the window. Because of this, the particular electrodes
45
have to be provided which makes the size of the apparatus large.
As to unevenness of film deposited by CVD, it is also the problem in the case of plasma CVD. The energy of plasma seems dependent on the relationship between the substrate and a pair of electrodes for discharge. So a uniform deposition condition on a substrate to be coated is also demanded for plasma CVD.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide an CVD apparatus with which a film can be deposited with a uniform thickness.
It is another object of the invention to provide a CVD apparatus with which a film can be deposited with high quality.
It is a further object of the invention to provide a cheaper CVD apparatus.
It is still a further object of the invention to provide a compact CVD apparatus.


REFERENCES:
patent: 4015558 (1977-04-01), Small et al.
patent: 4495218 (1985-01-01), Azuma et al.
patent: 4546535 (1985-10-01), Shepard
patent: 4579609 (1986-04-01), Reif et al.
patent: 4597986 (1986-07-01), Scapple et al.
patent: 4601260 (1986-07-01), Ovshinsky
patent: 4634496 (1987-01-01), Mase et al.
patent: 4636401 (1987-01-01), Yamazaki et al.
patent: 4657616 (1987-04-01), Benzing et al.
patent: 4705912 (1987-11-01), Nakashima et al.
patent: 4848272 (1989-07-01), Ohmura et al.
patent: 4857139 (1989-08-01), Tashiro et al.
patent: 4894352 (1990-01-01), Lane et al.
patent: 5389581 (1995-02-01), Freiberger et al.
patent: 5650013 (1997-07-01), Yamazaki
patent: 52-75183 (1977-06-01), None
patent: 55-014138 (1980-04-01), None
patent: 58-197856 (1983-11-01), None
patent: 60-145628 (1985-08-01), None
patent: 61-110772 (1986-05-01), None
patent: 61-289649 (1986-12-01), None
patent: 62-045022 (1987-02-01), None
patent: 62-216318 (1987-09-01), None
patent: 63-314828 (1989-04-01), None
patent: 02-129371 (1990-05-01), None
“Reactive Ion Etching for Silicon and Silicon Dioxide with Nitrogen Trifluoride”, Sci. Eng. Rev. Doshisha Univ. (1984), 24(4); abstract.*
“Plasma Enhanced Chemically Vapour-Deposited Silicon Dioxide for Metal/Oxide/Semiconductor Structures on InSb”; Thin Solid Films (Nov. 5, 1982), vol. 97, No. 1, abstract, Mackens et al.*
“Investigation of Silicon Dioxide Layers Deposited by Plasma Decomposition of Tetra-Ethoxy Silane in a Planar Reactor”; Kirov et al.; Phys. Status Solidi A (1978), 48(2), abstract.

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