Data processing: generic control systems or specific application – Specific application – apparatus or process – Article handling
Reexamination Certificate
1998-07-30
2001-08-14
Skaggs, H. Grant (Department: 3651)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Article handling
C414S935000, C414S937000
Reexamination Certificate
active
06275744
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the art of controlling the feeding of substrates with respect to a plurality of processing chambers of a substrate processing apparatus such as a semiconductor fabrication apparatus for forming films on semiconductor substrates or an LCD (liquid crystal display) fabrication apparatus for forming films on glass substrates for LCD.
2. Description of the Related Art
One known substrate processing apparatus for successively processing substrates in a plurality of processing chambers finds its use as an LCD fabrication apparatus of the single-substrate in-line processing type which processes a substrate or a small number of substrates successively as shown in
FIG. 17
of the accompanying drawings.
The LCD fabrication apparatus shown in
FIG. 17
has an atmospheric substrate feeder T
1
coupled to a loading cassette stand S
1
, an auxiliary substrate loading chamber L
1
coupled to the atmospheric substrate feeder T
1
by a gate valve LV
1
, a vacuum substrate feeder T
2
coupled to the auxiliary substrate loading chamber L
1
by a gate valve LV
2
, and an auxiliary substrate heating chamber H coupled to the vacuum substrate feeder T
2
.
A vacuum substrate feeder T
3
is coupled to the auxiliary substrate heating chamber H by a gate valve LV
3
. First, second, and third film growing chambers R
1
, R
2
, R
3
are coupled to the vacuum substrate feeder T
3
by respective gate valves LV
4
, LV
5
, LV
6
.
A vacuum substrate feeder T
4
is coupled to the third film growing chamber R
3
by a gate valve LV
7
. Fourth and fifth film growing chambers R
4
, R
5
are coupled to the vacuum substrate feeder T
4
by respective gate valves LV
8
, LV
9
. A buffer chamber B
1
is coupled to the vacuum substrate feeder T
4
. A vacuum substrate feeder T
5
is coupled to the buffer chamber B
1
. Sixth, seventh, and eighth film growing chambers R
6
, R
7
, R
8
are coupled to the vacuum substrate feeder T
5
by respective gate valves LV
10
, LV
11
, LV
12
. A vacuum substrate chamber T
6
is coupled to the eighth film growing chamber R
8
by a gate valve LV
13
.
An auxiliary substrate unloading chamber L
2
is coupled to the vacuum substrate chamber T
6
by a gate valve LV
14
. An atmospheric substrate feeder T
7
is coupled to the auxiliary substrate unloading chamber L
2
by a gate valve LV
15
. An unloading cassette stand S
2
is coupled to the atmospheric substrate feeder T
7
.
The vacuum substrate feeders are housed in feed chambers. The film growing chambers serve as processing chambers for growing films on substrates therein. The heating chamber serves as a chamber for heating a substrate therein. Therefore, the chambers of the LCD fabrication apparatus serve as processing chambers for processing substrates in predetermined fashions.
A substrate loaded into the LCD fabrication apparatus is processed in the processing chambers as it is fed successively therethrough by the feeders. After desired films have been formed on the substrate, the substrate is unloaded from the LCD fabrication apparatus.
The feeding of substrates successively through the processing chambers and the processing of those substrates in the processing chambers are controlled by a controller (not shown).
Efforts have been made to increase the throughput of the LCD fabrication apparatus. For example, identical films are formed on substrates in the first and second film growing chambers R
1
, R
2
. Since the same films are formed on the substrates in the two film growing chambers, the throughput can be increased when successive substrates are introduced into the LCD fabrication apparatus.
For such simultaneous processing, the substrates need to be fed into the first and second film growing chambers R
1
, R
2
by the vacuum substrate feeder T
3
. Consequently, the vacuum substrate feeder T
3
is subject to an conflict between feed job requirements for feeding substrates into the two film growing chambers simultaneously.
The LCD fabrication apparatus of the single-substrate in-line processing type takes up a relatively large installation space and is relatively expensive because it has many substrate feeders (seven feeders in FIG.
17
). To eliminate these drawbacks, there have been employed substrate processing apparatus of the single-substrate cluster type in recent years.
The substrate processing apparatus of the single-substrate cluster type comprises a plurality of processing chambers coupled to a main frame which houses substrate feeders. Some of the processing chambers serve as film growing chambers for processing substrates identically, and substrates are fed into these film growing chambers by one substrate feeder.
Inasmuch as such one substrate feeder is required to feed many substrates into the respective film growing chambers, the substrate feeder is also subject to a feed job conflict in feeding substrates into the film growing chambers.
Such a feed job conflict can be avoided by setting up a suitable feed job schedule for establishing a sequence of individual feed jobs. However, unless a suitable feed job schedule is set up, a substrate may be exposed to an environment in which its temperature cannot properly be controlled for a long period of time, e.g., a substrate may remain gripped by the substrate feeder and stay in an undesirable temperature environment for a long period of time, and may be given an unwanted heating history, resulting in a reduction in substrate yield. This problem also arises with respect to the substrate processing apparatus of the single-substrate in-line processing type, but is more serious with the substrate processing apparatus of the single-substrate cluster type.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to control the feeding of substrates smoothly with a substrate feeder for a high throughput in view of time intervals at which substrates can be loaded into a substrate processing apparatus.
Another object of the present invention is to prevent substrates from staying undelivered undesirably in a substrate processing apparatus for thereby preventing substrate products from suffering a reduction in quality due to an undesirable heating history.
According to the present invention, a processing chamber or processing chambers for identically processing substrates are handled as a processing chamber group, and a substrate processing apparatus has a plurality of processing chamber groups including at least one processing chamber group of a plurality of processing chambers for identically processing substrates concurrently therein, and a substrate feeder for feeding substrates to each of the processing chamber groups. In order to prevent substrates successively loaded into the substrate processing apparatus from staying undelivered in the substrate processing apparatus, time intervals at which substrates are loaded into the substrate processing apparatus are considered, and times required to complete feed jobs to feed substrates are assigned to the feed jobs in association with the time intervals. The feed jobs are performed according to the assigned times.
Specifically, the sums of times required to process substrates in the processing chambers and times required to feed substrates to the processing chambers are divided by the number of the processing chambers included in the processing chamber groups, and a time equal to or greater than a maximum one of the calculated times of each chamber group is established as a tact time. Substrates to be processed are loaded into the substrate processing apparatus with the substrate feeder at intervals of the tact time.
The tact time thus determined is effective to prevent substrates successively loaded into the substrate processing apparatus from staying undelivered due to intervals at which they are loaded.
A time equal to or greater than a time required for the substrate feeder to perform a feed job is established as a feed slot, and a plurality of feed slots are established in the tact time, which substrates are fed to the process
Kokusai Electric Co. Ltd.
Skaggs H. Grant
Tran Khoi H.
Wenderoth , Lind & Ponack, L.L.P.
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