Classifying – separating – and assorting solids – Sorting special items – and certain methods and apparatus for... – Condition responsive means controls separating means
Reexamination Certificate
1999-10-28
2001-07-24
Walsh, Donald P. (Department: 3653)
Classifying, separating, and assorting solids
Sorting special items, and certain methods and apparatus for...
Condition responsive means controls separating means
C209S577000, C209S587000, C235S462010, C235S462110
Reexamination Certificate
active
06265684
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to an optical sorting system. More particularly, the present invention relates to a wafer ID optical sorting system employed in the semiconductor fabrication process.
2. Description of Related Art
Wafers
10
,
20
fabricated in the semiconductor fabrication process each have their own IDs
12
,
22
, which are located opposite the notch
14
or the flat
24
, as shown in FIG.
1
. The IDs
12
,
22
contain a lot number and a barcode, and are formed on the wafers
10
,
20
by a laser. The IDs
12
,
22
of each wafer
10
,
20
are different from each other to allow easy recognition of the wafers
10
,
20
.
When an entire lot of wafers has completed a semiconductor fabrication process, sometimes a portion of the wafers does not meet the process requirements for, for example, film deposition or removal of photoresist. Therefore, a sorter machine with an auto ID reader is used to recognize automatically the ID of the wafer, such that trouble shooting can be performed. However, the auto ID reader may fail to read the ID when the photoresist or the material formed on the ID cannot be completely exposed or etched in such processes as wafer edge exposure or edge clamp process variation, resulting in wafer edge color difference. These various imperfections render the auto ID reader unable to clearly identify the ID.
In addition, if the ID is retrieved from the chamber and then identified by the naked eye, the wafer ID cannot be clearly recognized and the wafer is easily contaminated with particles. Additionally, the larger the wafer is, the more difficult it is to draw out and store, so that it is necessary to pay more attention to prevent the wafer from falling when the wafer is in operation. Accordingly, the cycle time in operation is increased and performance is decreased.
SUMMARY OF THE INVENTION
The invention provides a wafer ID optical sorting system to successfully identify the wafer ID of a semiconductor wafer.
As embodied and broadly described herein, the invention provides a wafer ID optical sorting system including an auto-ID reader, a manual-ID reader and a conveying device, operation of which units is controlled by a monitoring system. The auto-ID reader, connected to the monitoring system, can automatically read and identify an ID and allows the ID to be displayed on the monitoring system. The manual-ID reader, connected to the monitoring system, can fetch the ID image and allows it to be displayed on the monitoring system. The conveying device, connected to the monitoring system, can move the auto-ID reader and the manual-ID reader. The auto-ID reader includes an ID reader and a first charge coupled device, the manual-ID reader includes an optical magnifying device and a second charge coupled device, and the monitoring system includes a monitor and a control panel.
The invention provides a method of identifying a wafer ID. A wafer is moved from a cassette to an auto-ID reader by way of the conveying system, and the auto-ID reader is used to identify the ID of the wafer. When the ID cannot be successfully identified by the auto-ID reader, the wafer is then moved from the auto-ID reader to a manual-ID reader by the conveying system. The manual-ID reader fetches the ID image, which is displayed by a monitoring system. Thereafter, the wafer is returned to the cassette by the conveying device.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.
REFERENCES:
patent: 5175774 (1992-12-01), Truax et al.
patent: 5386481 (1995-01-01), Hine et al.
patent: 5759006 (1998-06-01), Miyamoto et al.
patent: 5864130 (1999-01-01), Kahn et al.
patent: 5894348 (1999-04-01), Bacchi et al.
patent: 6027301 (2000-02-01), Kim et al.
Jiawei Huang
Miller Jonathan R.
Patents J. C.
ProMOS Technologies Inc.
Walsh Donald P.
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