Electric heating – Metal heating – By arc
Reexamination Certificate
2001-12-07
2004-06-22
Van, Quang T. (Department: 3742)
Electric heating
Metal heating
By arc
C219S121540, C118S7230MW, C204S298380
Reexamination Certificate
active
06753496
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to plasma processing apparatuses. In particular, the present invention relates to a plasma processing apparatus such as etching, film deposition and ashing apparatuses used for manufacturing semiconductor devices or liquid crystal display devices, for example.
2. Description of the Background Art
A plasma process by means of microwave now captures attention as that is applicable to a low-temperature plasma process for a semiconductor device or TFT (thin film transistor) liquid crystal display device for example. What is important here is that such a plasma process is uniformly carried out for a substrate. In addition, under a low gas-pressure condition of 0.133 Pa or lower, discharge tends to be difficult to start. This tendency is pronounced particularly when a gas with a high ionization voltage is used.
These problems are addressed as disclosed in Japanese Patent Laying-Open Nos. 5-36641 and 2000-91097 showing methods for achieving uniform plasma and in Japanese Patent Laying-Open No.9-232099 showing a method for improving a plasma generation property.
The method disclosed in Japanese Patent Laying-Open No. 5-36641 is described below.
FIG. 13
is a schematic cross section showing a structure of a plasma processing apparatus disclosed in Japanese Patent Laying-Open No. 5-36641. Referring to
FIG. 13
, a chamber body
101
and a dielectric plate
103
are sealed by an O-ring (not shown) in order to isolate a process chamber
100
from the atmosphere. The air inside process chamber
100
is discharged by an exhaust device (not shown) until a predetermined vacuum pressure is attained. Then, a process gas is supplied from a gas inlet
109
into process chamber
100
. A microwave generated by a microwave generator (not shown) is thereafter supplied through a waveguide
106
into a microwave stirrer chamber
102
. An impeller
108
is rotated by a drive motor
107
to stir and disperse the microwave within microwave stirrer chamber
102
. The stirred microwave is passed through dielectric plate
103
into process chamber
100
. The process gas is thus excited to generate plasma. This plasma is used to plasma-process a substrate
105
held on a substrate holder
104
.
Japanese Patent Laying-Open No. 2000-91097 discloses a technique as discussed below.
FIGS. 14 and 15
are schematic cross sectional and plan views respectively of a structure of a plasma processing apparatus disclosed in Japanese Patent Laying-Open No. 2000-91097. Referring to
FIGS. 14 and 15
, the air inside a process chamber
100
is discharged by an exhaust device (not shown) until a predetermined vacuum pressure is attained, and a process gas is thereafter supplied from a gas inlet
109
. A microwave generated by a microwave generator
122
is guided though a waveguide
114
and a dielectric line
115
to the top of process chamber
100
. The microwave radiated from dielectric line
115
is passed though a microwave dispersion plate
120
formed of three plates stacked on each other as well as a microwave entrance window
116
into process chamber
100
for generating plasma from the process gas. Then, a substrate
105
held on a substrate holder
104
is plasma-processed.
Microwave dispersion plate
120
is constituted of two dielectric plates
117
and
119
and a plurality of thin aluminum sheets
118
arranged at certain intervals between the two dielectric plates, and this microwave dispersion plate
120
serves to disperse the microwave.
Japanese Patent Laying-Open No. 9-232099 discloses a technique as described below.
FIG. 16
is a schematic cross section showing a structure of a plasma processing apparatus disclosed in Japanese Patent Laying-Open No. 9-232099. Referring to
FIG. 16
, the air inside a process chamber
100
is discharged by an exhaust device (not shown) until a predetermined vacuum pressure is attained and then a process gas is supplied from a gas inlet
109
. A microwave generated by a microwave generator
123
is guided through a waveguide
124
via a matching unit
125
to the top of a microwave entrance window
126
. Then, the microwave is passed through microwave entrance window
126
made of dielectric to be radiated into process chamber
100
. On one side of microwave entrance window
126
that faces process chamber
100
, a depression
126
a
is provided. The process gas supplied from gas inlet
109
into process chamber
100
is excited by the microwave radiated from microwave entrance window
126
to generate plasma. Then, a substrate
105
on a substrate holder
104
is plasma-processed.
Depression
126
a
which deforms microwave entrance window
126
can cause plasma concentration so that the plasma generation property can be improved.
However, the plasma process is difficult to make uniform by the methods described above when the methods are used for a TFT liquid crystal display device with a substrate of a size ranging from 500×500 mm to 1 m×1 m. There are thus problems in respective methods described above.
In the apparatus of Japanese Patent Laying-Open No. 5-36641, the microwave is stirred by impeller
108
and then supplied into process chamber
100
. This is effective to some degree for circular substrate
105
. However, the microwave uniformity is unsatisfactory for a rectangular substrate. Moreover, although impeller
108
is advantageously used to apply the microwave almost uniformly to a substrate of a small area, such a microwave is difficult to apply to a rectangular substrate of a large area. In other words, it is considerably difficult to design stirrer chamber
102
and impeller
108
that are to be used for uniformly supplying the microwave into process chamber
100
.
A plurality of stirrer chambers
102
and impellers
108
might be provided. However, problems arise in terms of control of impellers
108
and maintenance.
In the apparatus of Japanese Patent Laying-Open No. 2000-91097, the microwave is dispersed by microwave dispersion plate
120
. The performance of microwave dispersion plate
120
is determined by the thickness and arrangement of aluminum sheets
118
between two dielectric plates
117
and
119
. However, optimization of the thickness and arrangement of aluminum sheets
118
for the purpose of dispersing and uniformly supplying the microwave is difficult to accomplish. In addition, it is hard to produce microwave dispersion plate
120
which is applicable to large-area substrates.
This plasma processing apparatus uses dielectric line
115
from which the microwave is supplied. Dielectric line
115
guides the microwave generated by generator
122
to the top of process chamber
100
so as to radiate the microwave into chamber
100
from a radiation plate which is larger in size than substrate
105
. Dielectric line
115
is made of dielectric such as Teflon (trade name) that includes a tapered portion T with its width increasing from the one on one end corresponding to the width of the output opening of generator
122
to the width on the other end corresponding to the width of the microwave radiation portion. In order to transmit the microwave without change of the propagation mode, tapered portion T of dielectric line
115
should gradually be tapered. Then, in order to adapt dielectric line
115
to a large-area substrate, tapered portion T is made considerably long. Consequently, when the apparatus is used for a large substrate
105
, the apparatus increases in size to occupy a large installation area.
In the apparatus of Japanese Patent Laying-Open No. 9-232099, depression
126
a
is provided as shown in
FIG. 16
on the side of microwave entrance window
126
that faces process chamber
100
in order to improve the plasma generation property. Depression
126
a
is utilized to cause, in process chamber
100
, a high field-intensity region to be generated near depression
126
a
in order to facilitate plasma generation.
The presence of the high field-intensity region in the apparatus certainly improves the plasma generation property. However, th
Hirayama Masaki
Ohmi Tadahiro
Tadera Takamitsu
Yamamoto Tatsushi
Conlin David G.
Edwards & Angell LLP
Hazzard Lisa Swiszcz
Sharp Kabushiki Kaisha
Van Quang T.
LandOfFree
Plasma processing apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Plasma processing apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Plasma processing apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3309648