Coating apparatus – Gas or vapor deposition – With treating means
Reexamination Certificate
2001-08-24
2002-12-31
Mills, Gregory (Department: 1763)
Coating apparatus
Gas or vapor deposition
With treating means
C118S719000, C156S345310, C156S345320
Reexamination Certificate
active
06499427
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a plasma CVD apparatus for forming a thin film in the semiconductor, liquid crystal, optical disc or like technological fields, and particularly relates to a plasma CVD apparatus using a reaction chamber constituted by a conductor such as metal.
2. Description of the Related Art
As methods of forming a thin film on a substrate, there are known a sputtering method using a sputtering phenomenon in a decompressed state, a vacuum evaporation method using an evaporation phenomenon, a CVD (Chemical Vapor Deposition) method such as a plasma CVD method using low temperature gas decomposition by plasma, a thermal CVD method using heat decomposition of a gas, and a photo CVD method for decomposing a gas by energy of shortwave light or ultraviolet rays, and the like. In addition, research and development has been undertaken with respect to combined techniques and applied techniques of the aforementioned methods, and such techniques have been implemented in actual manufacturing methods.
Among the foregoing thin film forming techniques, the plasma CVD method is characterized in that direct current or high frequency voltage is applied to a reaction gas in a decompressed state, and the reaction gas is decomposed by glow discharge to deposit a film on a substrate. In the thin film formation by this method, gas can be decomposed at a relatively low temperature (500° C. or less) by plasma energy such as high electron temperature of several eV in the plasma, and films of various compositions with high purity can be formed by using vacuum and by changing the kind of gas. Thus, the plasma CVD method is used in various fields such as the semiconductor field, the liquid crystal field, the optical disk field, and the magnetic disk field. magnetic disk field.
It is well known that to use a batch type plasma CVD apparatus in which a plurality of substrates are processed at the same time to form a thin film on a substrate.
However, in the case of the batch process, even if substrates are processed at the same time, characteristics of thin films slightly fluctuate in the respective substrates. Thus, repeated or consistent precision is poor and unevenness among substrates is large, so that the batch process has not been able to fulfill the desire for high precision in a thin film.
In addition, since a plurality of (about four to eight pieces) substrates are processed at the same time, it has been necessary to provide a substrate holder on which the substrates are mounted and are moved together with the substrates. This substrate holder is removed to the outside of the plasma CVD apparatus when film growth on the substrates is completed, the next batch of substrates is mounted on the substrate holder, and then the substrate holder is again processed in the apparatus.
Thus, since the process of heating in vacuum and placing in atmospheric pressure at room temperature is repeated, a so-called peeling phenomenon occurs in which a film attached to the substrate holder is peeled off.
Because of the foregoing reason, the batch process has not been used recently in not only the plasma CVD apparatus but also in almost entire fields including, for example, thin film etching. Instead, single wafer processing type apparatus has been used.
The single wafer processing type is a system characterized in that a substrate holder moving together with substrates is not used, but, rather, substrates are processed one by one, and only the substrate is moved. A conventional plasma CVD apparatus using this system will be described with reference to
FIGS. 2 and 3
.
FIG. 2
is a top view showing a single wafer processing type plasma CVD apparatus, and a chamber
201
is a load chamber in and out of which a substrate is carried. Chambers
202
to
206
become reaction chambers.
A plurality of substrates to be processed are set in the load chamber
201
by a cassette or the like. After the substrates are set in the load chamber
201
, the chamber is decompressed. When the chamber is decompressed to a sufficient pressure, a gate valve
210
between the load chamber
201
and a common chamber
207
is opened. A substrate carrying means
208
disposed in the common chamber
207
carries one substrate among a plurality of substrates set in the cassette in the load chamber
201
from the load chamber
201
into the common chamber
207
.
FIG. 2
shows the state where the substrate has been carried, and a substrate
209
is carried into the reaction chamber in which a thin film is formed. The substrate
209
is carried by the substrate carrying means
208
into the reaction chamber.
The common chamber
207
is connected to the respective reaction chambers
202
to
206
and the load chamber
201
through the respective gate valves
210
. When the substrate
209
is carried in and out of the respective chambers, the gate valve of that chamber is opened. The load chamber
201
, the respective reaction chambers
202
to
206
, and the common chamber
207
are evacuated by vacuum exhausting means, respectively.
As to thin film formation, there are various types such as a lamination type (P-layer, I-layer, and N-layer, etc.)for use, for example, in an amorphous solar cell, and a single layer type for use, for example, in a protective film for a semiconductor. Thus, the processes in the respective chambers are different according to the kinds of films to be formed, the type of lamination, and the like.
FIG. 3
is a sectional view taken along line A—A of FIG.
2
and showing the common chamber
207
and the reaction chamber
204
.
An electrode
211
and a substrate holder
212
are disposed in the reaction chamber
204
. The electrode
211
is connected to a power source
213
, and the substrate holder
212
and the reaction chamber
204
are grounded. The substrate holder
212
is equipped with a heater (not shown) for heating a substrate.
This substrate holder
212
is disposed inside the reaction chamber
204
contrary to the foregoing batch type, and is not moved together with the substrate
209
.
The substrate
209
is placed on the substrate holder
212
from the common chamber
207
, and a reaction gas is introduced through an introduction pipe
214
. Then voltage is applied to the electrode
211
to generate plasma in a space
215
so that a thin film is formed on the substrate.
The substrate
210
on which a thin film has been formed, is again carried by the carrying means
208
in the common chamber
207
from the reaction chamber
204
into the common chamber
207
, and is subjected to a next process. Another substrate is carried in the reaction chamber
204
and thin film formation is performed in the same manner. In these sequential processes, only the substrate is moved.
Incidentally, reference numerals
217
and
218
denote vacuum exhausting means, which maintain the inside of the common chamber and the reaction chamber in a decompressed state. The exhausting means is generally independently provided in the respective chambers.
The reaction cambers
203
to
206
also have the same structure as the reaction chamber
202
, and the reaction chambers are selectively used according to the kind and thickness of a film to be formed. For example, a silicon film is formed in the reaction chamber
202
, a silicon oxide film is formed in the reaction chamber
203
, and a silicon nitride film is formed in the reaction chamber
204
.
Alternatively, the same process of laminating a silicon nitride film, a silicon film, and a silicon nitride film is performed in the respective reaction chambers, so that the total throughput, that is, the so-called producibility is improved.
Of course, if the kind of film to be formed in each chamber is determined so as to suppress impurities to the highest degree, each film can be sequentially formed without mixture of impurities, so that it is also possible to increase the efficiency of production.
In the structure of the above-mentioned plasma CVD apparatus, the respective chambers are mainly composed of a conductor such
Abe Hisashi
Ishiwata Mika
Sakama Mitsunori
Takayama Toru
Uehara Hiroshi
Mills Gregory
Robinson Eric J.
Robinson Intellectual Property Law Office P.C.
Semiconductor Energy Laboratory Co,. Ltd.
Zervigon Rudy
LandOfFree
Plasma CVD 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 CVD apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Plasma CVD apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2989246