Coating processes – Direct application of electrical – magnetic – wave – or... – Plasma
Reexamination Certificate
2001-12-10
2004-02-24
Padgett, Marianne (Department: 1762)
Coating processes
Direct application of electrical, magnetic, wave, or...
Plasma
C427S570000, C216S071000, C118S7230ER
Reexamination Certificate
active
06696108
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a vacuum processing method using a high-frequency power, which is used for forming a deposited film, etching and so on in semiconductor devices, electrophotographic photosensitive members, image input line sensors, photographing devices, photovoltaic devices and so on.
2. Related Background Art
As for deposited film forming methods used for semiconductor devices, electrophotographic photosensitive members, image input line sensors, photographing devices, photovoltaic devices, other various electronic elements and optical elements, many methods such as a vacuum evaporation method, a sputtering method, an ion plating method, a thermal CVD method, an photo-chemical vapor deposition method and a plasma CVD method are conventionally known, and apparatuses therefor are put into practice.
Among others, the plasma CVD method, that is, a method of decomposing a material gas by a direct current or a high-frequency or a microwave glow discharge to form a thin film-like deposited film on a substrate is currently so commercialized as a suitable method for forming a hydrogenated amorphous silicon deposited film for an electrophotography and so on, and various apparatuses for the method therefor are proposed.
Here, a deposited film forming apparatus using the plasma CVD method will be described by referring to FIG.
4
.
FIG. 4
is a schematic block diagram showing an example of the conventional deposited film forming apparatus by a RF plasma CVD method using an RF-band frequency as a power supply, which is specifically an apparatus for forming a light-receiving member for an electrophotography.
If roughly divided, this apparatus is comprised of a deposition apparatus
2100
, a material gas supplying apparatus
2200
and an exhauster (not shown) for reducing pressure in a reaction container
2101
. The reaction container
2101
of the deposition apparatus
2100
has a cylindrical substrate
2112
, a substrate supporter
2113
containing a substrate heater
2113
a
and a material gas admitting pipe
2114
installed therein, and furthermore, a high-frequency matching box
2115
is connected to a cathode electrode
2111
constituting a part of the reaction container
2101
. The cathode electrode
2111
is insulated from an earth potential by an insulator
2120
, and a high-frequency voltage is applicable between it and the cylindrical substrate
2112
also serving as an anode electrode maintained at the earth potential through the substrate supporting member
2113
.
The material gas supplying apparatus
2200
is comprised of a plurality of gas cylinders
2221
to
2226
for accommodating material gases such as SiH
4
, GeH
4
, H
2
, CH
4
, B
2
H
6
and PH
3
, gas cylinder valves
2231
to
2236
, gas inflow valves
2241
to
2246
, gas outflow valves
2251
to
2256
and massflow controllers
2211
to
2216
, where each material gas cylinder is connected to the gas admitting pipe
2114
in the reaction container
2101
via a material gas piping
2116
having a supplementary valve
2260
.
Formation of the deposited film of which main component is silicon by using the deposited film forming apparatus thus constituted is performed as follows for instance.
First, the cylindrical substrate
2112
is set in the reaction container
2101
, and air is exhausted from inside the reaction container
2101
by an exhauster (a vacuum pump for instance) that is not shown. Subsequently, the substrate heater
2113
a
built into the substrate supporting member
2113
controls a temperature of the cylindrical substrate
2112
to be the predetermined temperature between 200° C. and 350° C.
To admit the material gas for forming the deposited film into the reaction container
2101
, it is checked that the gas cylinder valves
2231
to
2236
and a leak valve
2117
of the reaction container
2101
are closed, and it is also checked that the gas inflow valves
2241
to
2246
, gas outflow valves
2251
to
2256
and the supplementary valve
2260
are open, and then a main valve
2118
is opened first to exhaust air from inside the reaction container
2101
and the material gas piping
2116
.
Next, the supplementary valve
2260
and the gas outflow valves
2251
to
2256
are closed when a vacuum gage
2119
reads approximately 7×10
−1
Pa.
Subsequently, the gas cylinder valves
2231
to
2236
are opened to let the gases in from the gas cylinders
2221
to
2226
, and each gas pressure is adjusted to be 0.2 Mpa by pressure regulators
2261
to
2266
.
Next, the gas inflow valves
2241
to
2246
are gradually opened to admit the gases into the massflow controllers
2211
to
2216
.
After preparation for film formation is completed as above, each layer is formed by means of the following procedure.
When the cylindrical substrate
2112
reaches the predetermined temperature, necessary ones of the gas outflow valves
2251
to
2256
and the supplementary valve
2260
are gradually opened to admit predetermined gases into the reaction container
2101
from the gas cylinders
2221
to
2226
via the material gas admitting pipe
2114
. Next, an adjustment is made by a predetermined massflow controller of the massflow controllers
2211
to
2216
so that each material gas will have a predetermined flow rate. At that time, openness of the main valve
2118
is adjusted by checking the vacuum gage
2119
so that the pressure in the reaction container
2101
will be a predetermined value.
When internal pressure of the reaction container
2101
becomes stable, an RF power supply of 13.56 MHz frequency (not shown) is set at a desired power, and the RF power is admitted into the reaction container
2101
through the high-frequency matching box
2115
and the cathode electrode
2111
so that the cylindrical substrate
2112
acts as an anode to generate the glow discharge. This discharge energy decomposes the material gases admitted in the reaction container
2101
to form the predetermined deposited film of which main component is silicon on the cylindrical substrate
2112
.
After a desired film thickness is formed, supply of the RF power is stopped, and the gas outflow valves
2251
to
2256
are closed to stop inflow of the gases into the reaction container
2101
so as to finish formation of the deposited film. A light-receiving layer having a desired multi-layer structure can be formed by repeating the same operations a plurality of times.
It is needless to say that, when forming each layer, all the gas outflow valves
2251
to
2256
other than those for necessary gases are closed, and as required, an operation of closing the gas outflow valves
2251
to
2256
and opening the supplementary valve
2260
and further fully opening the main valve
2118
is performed to make the inside of the system a high vacuum once and exhaust air from inside the piping for the purpose of avoiding remaining of each gas in the reaction container
2101
and in the piping from the gas outflow valves
2251
to
2256
to the reaction container
2101
.
Moreover, to ensure the uniform film thickness and film quality, it is effective to rotate the cylindrical substrate
2112
with a driving system (not shown) at a predetermined speed while forming a layer. Furthermore, it is needless to say that the above-mentioned gas types and valve operations are changed according to conditions for making each layer.
In addition to such conventional deposited film forming apparatuses and methods by an RF plasma CVD method using the above RF-band frequency, a VHF plasma CVD method using a high-frequency power in a VHF band (hereinafter, referred to as the “VHF-PCVD method”) is receiving attention in recent years, and development of various types of deposited film formation is actively underway. This is because it is expected that, as the VHF-PCVD method allows a high speed of film deposition and acquisition of a high quality deposited film, it is possible to simultaneously accomplish lower costs and higher quality of products. For instance, Japanese Patent Application La
Aoki Makoto
Murayama Hitoshi
Niino Hiroaki
Shirasuna Toshiyasu
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Padgett Marianne
LandOfFree
Vacuum processing method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Vacuum processing method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Vacuum processing method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3309968