Drying and gas or vapor contact with solids – Apparatus – With apparatus using centrifugal force
Reissue Patent
2000-07-07
2001-09-04
Gravini, Stephen (Department: 2162)
Drying and gas or vapor contact with solids
Apparatus
With apparatus using centrifugal force
C134S902000
Reissue Patent
active
RE037347
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a substrate gripper device for gripping a substrate such as a semiconductor substrate, a glass substrate, a liquid-crystal panel, or the like which needs to be highly clean while the substrate is being cleaned or spin-dried.
2. Description of the Prior Art
As semiconductor devices become more highly integrated in recent years, line-widths of circuit interconnections become thinner and the distances between those interconnections also become smaller. While in various fabrication processes, fine semiconductor particles, dust particles, and peeled-off pieces such as crystalline bodies tend to be attached to semiconductor substrates. If foreign matter particles which is greater than the distance between interconnections existed on a semiconductor substrate, then a short circuit would be caused between the interconnections. Therefore, all foreign matter particles on semiconductor substrates have to be removed to avoid undesirable short circuits.
Such unwanted foreign matter particles also have to be removed from substrates with fine patterns thereon including glass substrates for use as masks and liquid-crystal panels during fabrication processes thereof. To meet the above requirements, there has been desired a cleaning technique for washing away fine foreign matter particles of submicron sizes from substrates such as semiconductor substrates.
While those substrates are being cleaned or subsequently spin-dried, they have to be reliably gripped by a substrate gripper device.
It has been widely practiced to rotate a substrate at high speeds ranging from 2000 to 3000 rpm while it is being gripped by a substrate gripper device for cleaning or spin-drying the substrate.
One conventional substrate gripper device is shown in
FIG. 1
of the accompanying drawings. As shown in
FIG. 1
, a plurality of support pins
2
are vertically mounted on a peripheral edge of a disk-shaped turntable (substrate stage)
1
which is rotatable at high speeds, and a substantially circular semiconductor substrate S is placed on and held by respective shoulders
3
of the support pins
2
. The substrate gripper device is disclosed in Japanese laid-open patent publication No. 4-53684, for example.
One problem with this substrate gripper device is that when the turntable
1
with the semiconductor substrate S supported thereon rotates at high speeds, the semiconductor substrate S is liable to lift off from the support pins
2
, and the substrate gripper device is incapable of reliably preventing the semiconductor substrate S from being lifted off from the support pins
2
.
FIG. 2
shows another known substrate gripper device disclosed in Japanese laid-open patent publication No. 3-30426, for example. As shown in
FIG. 1
, a circumferential edge of a semiconductor substrate S is gripped in place between upper surfaces of plural arms
4
extending radially outwardly and presser fingers
6
that are normally urged downwardly by respective springs
5
. For releasing the semiconductor substrate S, the substrate gripper device needs a mechanism for turning the pressing fingers
6
in an opening direction or lifting the pressing fingers
6
off the semiconductor substrate S. Since such a mechanism has to rotate with the semiconductor substrate S, it is considerably complex in structure. The entire assembly that rotates is relatively heavy, and cannot rotate at speeds beyond a certain speed limit.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a substrate gripper device which is relatively simple in structure, is capable of reliably gripping a substrate at its circumferential edge, can be handled with ease, and has a mechanism for opening and closing substrate grippers which is separate from a rotatable assembly, thereby minimizing the weight of the rotatable assembly and allowing the rotatable assembly to rotate at high speeds.
To achieve the above object, there is provided in accordance with the present invention a substrate gripper device for gripping a substrate, comprising a rotatable substrate stage, a plurality of fixing fingers mounted on an outer edge of the rotatable substrate stage and having respective substrate rests for placing thereon an outer edge of the substrate, a plurality of swing fingers angularly movably supported on the fixing fingers, respectively, for gripping the substrate in coaction with the fixing fingers, biasing means for normally biasing the swing fingers to move in a closing direction toward the fixing fingers, a plurality of opening pins disposed below the swing fingers, and movable upwardly for angularly moving the swing fingers in the opening direction against biasing forces of the biasing means, and an opening mechanism disposed below the substrate stage for simultaneously moving the opening pins upwardly.
The biasing means may comprise a plurality of helical springs acting on the swing fingers, respectively.
The opening mechanism may comprise a vertically movable cylindrical sleeve and an annular member fixed to an upper end of the vertically movable cylindrical sleeve, the annular member having an upwardly facing annular surface engageable with lower ends of the opening pins.
The substrate stage may be controlled to stop rotating in order to bring the opening pins above the opening mechanism.
With the above arrangement, the outer edge of the substrate is sandwiched between the fixing fingers and the swing fingers and firmly gripped therebetween under the bias of the biasing means. The opening mechanism, which is separate from the substrate stage, is moved upwardly to simultaneously lift all the opening pins for thereby releasing the substrate. The substrate gripper device is relatively simple in structure, and allows the substrate to rotate at high speeds as the rotatable assembly thereof, including the substrate stage, which is relatively small in weight.
The above and other objects, features, and advantages of the present invention will become apparent from the following description when taken in conjunction with the accompanying drawings which illustrate preferred embodiments of the present invention by way of example.
REFERENCES:
patent: 4651440 (1987-03-01), Karl
patent: 4677758 (1987-07-01), Aigo
patent: 4724619 (1988-02-01), Poli et al.
patent: 5174045 (1992-12-01), Thompson et al.
patent: 5566466 (1996-10-01), Hearne
patent: 5715610 (1998-02-01), Smith, Jr. et al.
patent: 5851041 (1998-12-01), Anderson et al.
patent: 5974681 (1999-11-01), Gonzalez-Martin et al.
patent: 62-60027 (1987-04-01), None
patent: 3-9607 (1991-02-01), None
Haraguchi Ryuji
Maekawa Toshiro
Ebara Corporation
Gravini Stephen
Wenderoth , Lind & Ponack, L.L.P.
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