Drying and gas or vapor contact with solids – Apparatus – With apparatus using centrifugal force
Reexamination Certificate
1998-10-14
2001-08-07
Wilson, Pamela (Department: 3749)
Drying and gas or vapor contact with solids
Apparatus
With apparatus using centrifugal force
C092S202000
Reexamination Certificate
active
06269548
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for providing processing such as dewatering and drying of workpieces such as washed semiconductor wafers, for example, while spinning the workpieces in a chamber defining a clean environment.
2. Description of the Related Art
In manufacturing processes for making semiconductor devices and liquid crystal displays, sometimes there is a need to quickly dry disk-shaped workpieces or wafers which have been subjected to rigorous washing steps. Some of such apparatuses are based on drying the wafer by spinning off the liquid by centrifugal force in a chamber of so-called spin drying apparatus. There are two types of spin drying apparatuses: a vertical type with a vertical spinning axis with the advantage of a small installation space, and a horizontal type with a horizontal spinning axis with the advantage of convenient vertical loading of wafers.
Both type of spin drying apparatuses share a common structural feature that a workpiece is held in a rotating wafer holder, having a rotation shaft extending along the rotational axis of the holder inside a chamber. In a widely used design for supporting the wafer holder, the rotation shaft is rotatably supported through a contact-type bearing and is united to a drive shaft of a drive device by mechanical coupling.
However, such contact-type bearing mechanisms for the rotation shaft are vulnerable to wear and generation of wear debris, presenting a problem of contamination of the wafers which had been subjected to careful cleaning. Another problem is that the service life of the bearing device is shortened by frictional wear, resulting in a lower operation efficiency due to frequent requirements for maintenance. The working environment is also degrade by noise generated by the operation of high-speed spin dryer.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a spin processing apparatus that can prevent contamination of workpieces by wear particles, and can operate at high efficiency while lowering the noise level associated with the operation of the apparatus.
Such object has been achieved in a spin processing apparatus for processing workpieces while rotating the same comprising: a chamber; a spin holder disposed inside the chamber for holding workpieces therein; a driver device for rotating the spin holder; a supporting device for rotatably supporting the spin holder in a non-contact manner through a magnetically-operated mechanism.
Accordingly, by rotatably supporting the spin holder in a non-contacting manner by using a magnetically-operated mechanism, generation of wear debris can be prevented. Lowering of service life due to wear of the rotation sections and associated noise generation can also be prevented.
The magnetically-operated mechanism may be comprised by radial magnetic bearing means for rotatably supporting a rotation shaft extending along a rotational axis of the spin holder, and axial magnetic bearing means.
The rotation shaft may be operatively joined to the driver device by way of magnetic coupling means in a non-contact manner. By using such a configuration and providing a in-between partition member, the interior space of the chamber can be separated from the drive-side devices so that cleanliness inside the chamber is improved. Also, residual vibrational movement of the spin holder can be prevented by the use of an anti-vibration positioning device.
The chamber may be provided with fluid handling means for introducing or discharging a gaseous or liquid medium. Accordingly, by introducing or discharging a gaseous or liquid medium while spin processing the workpieces, processes of cleaning and drying can be facilitated to increase the operational efficiency of the apparatus.
The apparatus may be provides with pressure control means for controlling a chamber pressure over a range of pressures from atmospheric pressure to a high vacuum. Accordingly, by controlling the interior pressure of the chamber, high vacuum or pressure variation can be utilized to perform various processes.
The magnetically-operated mechanism may be provided with gas flow means for eliminating particles residing in the mechanism by flowing a purge gas through the mechanism. According, further protection is provided to eliminate contamination of workpieces.
As explained above, the present spin processing apparatus utilizes magnetic bearings for rotating members to provide support in a non-contact manner, it is able to prevent generation of particles produced by wear of support members so that contamination arising from the apparatus can be prevented even for those workpieces requiring a high degree of cleanliness. Furthermore, loss of service life due to wear and the necessity for frequent inspections are reduced to provide high production efficiency, and the working environment is improved by reducing sources of noise generation.
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Hongo Akihisa
Maeda Kazuaki
Shinozaki Hiroyuki
Yoshioka Junichiro
Ebara Corporation
Wenderoth , Lind & Ponack, L.L.P.
Wilson Pamela
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