Data processing: generic control systems or specific application – Specific application – apparatus or process – Article handling
Reexamination Certificate
2002-06-03
2004-01-20
Tran, Khoi H. (Department: 3652)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Article handling
C700S258000, C414S937000
Reexamination Certificate
active
06681148
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a monitoring system for a conveying device for flat articles, especially wafers.
Wafers are thin disks of silicon, as they are used for the manufacture of integrated circuits, solar cells, etc. Such wafers must be handled extremely carefully in clean rooms, as they are transported, during the course of the manufacture of the integrated circuit, the solar cell, etc., from one processing step to a further processing step.
FIG. 3
shows a schematic view of an apparatus for carrying out various processing steps of a wafer.
Two racks
4
,
6
are disposed in a housing
2
that forms a supply or storage chamber; the racks have receptacles
8
(
FIG. 5
) that are disposed one above the other and in which can be accommodated disks
10
.
Via a motor
11
and by means of a device that is not illustrated in detail, the housing
2
can be displaced back and forth on a stationary rail
12
in the direction of the double arrow
14
, so that in one selected position, the one rack
4
, and in the other selected position, the other rack
6
, is located across from an opening
16
of a housing
18
that has further openings
20
to which the working chambers
22
are connected.
Disposed in a housing
18
is a robot
24
(
FIG. 4
) that is provided with a supporting arm
26
on which is disposed a carriage
28
. The carriage
28
has an indentation
30
, the base
32
of which is provided with vacuum slots
34
as well as capacitive proximity sensors
36
.
To move the supporting arm
26
, motors
38
and
40
are provided via which the supporting arm
26
is pivoted in a plane of movement that is perpendicular to a central axis of rotation of the robot
24
, and via which the spacing of the supporting arm from the axis of rotation can be altered. The carriage
28
can be rigidly connected to the supporting arm
26
, or can be displaceable on the carrying arm
26
via a non-illustrated further drive means.
FIG. 5
shows a perspective front view of the partially cut away or basically open toward the front housing
2
, whereby two chambers are visible, of which only the left one is provided with the rack
4
. The motor
10
serves for the back and forth movement of the housing
2
upon the rail
12
. As can be seen, the housing
2
is not directly displaceable on the rail
12
, but rather is disposed upon a frame element
42
that together with the housing
2
is displaceable along the rail
12
. The housing
2
can be displaced in height relative to the frame element
42
via a servo-motor
44
, in the direction of the double arrow
46
, so that the individual receptacles
8
, with the wafers
10
accommodated therein, though not illustrated in
FIG. 5
, can be positioned one after the other at the same height.
The construction and function of the previously described apparatus, various embodiments of which are offered in commerce by various firms, are known and will therefore not be described in detail.
The basic function is such that pursuant to
FIG. 3
, the robot
24
, in a one time lined-up, horizontal plane, introduces the carriage
28
out of the opening
16
and into an oppositely disposed receptacle of the rack
4
. With the aid of the servo motor
44
, the rack
4
is then lowered slightly vertically until the proximity sensors
36
register the approach of a wafer
10
that is disposed upon a base of a receptacle
8
. With a further lowering of the rack
4
, the wafer
10
comes to rest upon the base
32
of the indentation
30
, where it is held in place upon activation of the vacuum slots
34
. The carriage
28
subsequently moves out of the rack
4
into the interior of the housing
18
and through a first one of the openings
20
into a first one of the working chambers
22
, where it is deposited and processed. The wafer
10
is subsequently picked up by the carriage
28
and introduced into a next one of the working chambers, etc. until, after passing through the processing steps in the individual working chambers
22
, the wafer is deposited by the carriage
28
in the right rack
6
of
FIG. 3
, whereby pursuant to
FIG. 3
the housing
2
is moved toward the left. The carriage
28
is subsequently moved out of the rack
6
, the housing is moved toward the right and the next wafer is picked up from the rack
4
by first lowering the rack by the height of one receptacle, so that after the carriage
28
has been introduced into the next receptacle, and after a subsequent further lowering of the rack
4
, the next wafer
10
comes to rest on the carriage
28
.
The individual openings
16
and
20
of the housing
18
can be sealed off via vacuum-type slides, so that on the whole it is possible to operate under vacuum.
A problem that arises when processing with the described apparatus is that the carriage
28
that is moved by the robot
24
alters its horizontal plane of movement, either due to wear or due to high thermal stresses as it is introduced into the working chambers
22
, which are in part under high temperature. The vertical distance between the individual receptacles
18
in the racks
4
and
6
is relatively small, so that already a slight deformation or deflection of the carriage out of its targeted path of movement brings with it the danger that already upon its introduction into the rack
4
the carriage contacts a wafer and damages it, or that the wafer is then no longer satisfactorily deposited upon the carriage.
It is an object of the invention to provide a remedy for the aforementioned problem.
SUMMARY OF THE INVENTION
This object is realized by a monitoring system pursuant to the main claim.
The inventive monitoring system ensures that already slight deviations of the carriage movement from the targeted path of the carriage are detected and can be indicated. In this way, expensive damage to the wafers can be avoided.
It is to be understood that the inventive monitoring system for conveying devices pursuant to the main claim is suitable for many different types of flat articles, such as fragile, thin mica plates, thin ceramic plates, loaded printed circuit boards, etc. The inventive monitoring system is particularly well suited for conveying devices for wafers, the handling of which is subjected to particularly high requirements.
The dependent claims are directed to advantageous embodiments and further developments of the inventive monitoring system.
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patent: 5466945 (1995-11-01), Brickell et al.
patent: 5604443 (1997-02-01), Kitamura et al.
patent: 5605428 (1997-02-01), Birkner et al.
patent: 5906469 (1999-05-01), Oka et al.
patent: 6430468 (2002-08-01), Tepman et al.
patent: 6516244 (2003-02-01), Yoo et al.
patent: 43 26 309 (1984-09-01), None
patent: 43 10 149 (1994-10-01), None
JP 11179692.
JP 11150078.
JP 11254359.
JP 10041367.
Frisch Ernst Georg
Kollmer Xaver
Lettner Hans
Schindler Günther
Becker R W
Logitex Reinstmedientechnik GmbH
R W Becker & Associates
Tran Khoi H.
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