Material or article handling – Article reorienting device
Reexamination Certificate
1998-11-27
2001-02-06
Krizek, Janice L. (Department: 3652)
Material or article handling
Article reorienting device
C414S936000
Reexamination Certificate
active
06183189
ABSTRACT:
(1) TECHNICAL FIELD
This invention relates generally to wafer transfer and handling apparatus and more particularly to a mechanism for releasably holding and supporting a wafer in a wafer processing machine.
(2) DESCRIPTION OF THE PRIOR ART
The following three documents relate to methods dealing with wafer handling.
U.S. Pat. No. 5,643,366 issued Jul. 1, 1997 to Somekh et al., discloses wafer handling within a vacuum chamber using vacuum. The invention shows a robot insertion blade supports a wafer to be processed in a recess having conically sloping wafer holding surfaces which touch the wafer only at its outer periphery. Once positioned in the chamber, a set of three transfer finger with sloped contact surfaces supported from a “C” shaped support assembly raise the wafer adjacent to a susceptor bottom surface.
U.S. Pat. No. 4,724,621 issued Feb. 16, 1988 to Hobson et al., discloses a wafer processing chuck using slanted clamping pins. The invention shows lifting pins that receive a wafer from a transport device and lower the wafer to the surface of a chuck. Clamping pins lower and hold the wafer by means of enlargements on the ends of the clamping pins. Grooves on the surface of the chuck and internal channels in the chuck are used to supply gas to the back of the wafer for temperature control.
U.S. Pat. No. 4,619,573 issued Oct. 28, 1986 to Rathmann et al., teaches a wafer transport in the vacuum portion of an automated wafer processing machine that is accomplished by means of an improved transport mechanism.
With the existence of high throughput automatic process equipment, automatic wafer handling is most essential. The need for higher yield in the manufacture of semiconductor devices has driven the development and use of more highly automated semiconductor wafer handling apparatus. Furthermore, the need to reduce particulate levels in the processing areas has demanded the use of controlled wafer containment in which wafer transfer occurs. It is desirable that semiconductor wafer processing machines be easily reconfigurable to suit the needs of a particular manufacturing facility. Finally, any mechanical system which is to be part of a semiconductor wafer processing machine must be extremely reliable. This is due to the relatively high cost of down time in semiconductor facilities.
The prior art has failed to provide a wafer chuck apparatus which is simple, which reduces particulate generation, which is forgiving of the robotics handler positioning errors, and which is easily adaptable to various configurations of the machine in which it operates. The wafer transporting robot must be exacting in its handling of the fragile wafer and requires frequent calibration. Horizontal positioning is difficult to control as distances increase particularly with increasing wafer sizes and chamber dimensions. Degradation of the robot's precision will generate particulate contaminates (silicon chips and dust) within the PVD chamber thereby skewing the process. The prior art chuck does not provide sufficient tolerance for thermal expansion. Robot alignment must be done for each temperature set point, making it extremely inconvenient. Internal and environmental vibration will cause the wafer to bounce against the nesting locating pins thereby generating silicon dust.
DESCRIPTION OF THE INVENTION
In view of the prior art, it is a principle object of the present invention to provide an improved chuck apparatus for releasably holding and supporting a wafer within a wafer processing machine.
A further object of the present invention is to provide an efficient and reliable means for receiving the wafer from a wafer transport device while facilitating wafer alignment.
It is another object of the present invention to provide an efficient and reliable means for presenting and releasing the wafer to a wafer transport device without generating particulate contamination.
It is still another object of the present invention to provide a wafer chuck apparatus that is more forgiving of the robot's positioning errors.
It is yet another object of the present invention to easily reconfigure the wafer chuck apparatus to meet the needs of the particular processing machine.
These objects of the invention and other objects, features and advantages to become apparent as the specification progresses are accomplished by the invention, according to which, briefly stated, a group of lifting pins receives the wafer from the transport device and lowers the wafer to the chuck surface while banking the wafer against stationary locating pins on the chuck surface.
These and further constructional and operational characteristics of the invention will be more evident from the detailed description given hereafter with reference to the figures of the accompanying drawings which illustrate preferred embodiments and alternatives by way of non-limiting examples.
REFERENCES:
patent: 4619573 (1986-10-01), Rathmann et al.
patent: 4724621 (1988-02-01), Hobson et al.
patent: 5643366 (1997-07-01), Somekh et al.
patent: 1-140739 (1989-06-01), None
patent: 3-34345 (1991-02-01), None
patent: 4-80940 (1992-03-01), None
patent: 4-167541 (1992-06-01), None
Lin Charles
Lin Yih-Shung
Lzu Erzhuang
Tang Xiaosong
Chartered Semiconductor Manufacturing Ltd.
Krizek Janice L.
Pike Rosemary L. S.
Saile George O.
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