Fluid sprinkling – spraying – and diffusing – Combining of separately supplied fluids – Fluid streams have angular junction
Reexamination Certificate
2000-04-11
2002-05-14
Morris, Lesley D. (Department: 3752)
Fluid sprinkling, spraying, and diffusing
Combining of separately supplied fluids
Fluid streams have angular junction
C134S198000, C261S078200
Reexamination Certificate
active
06386466
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a cleaning apparatus which jets a cleaning liquid. More specifically, the invention relates to, although not restricted to, a cleaning apparatus particularly suitable for jetting a cleaning liquid at a surface of a workpiece, which has been cut by a cutter such as a semiconductor wafer dicer, to clean the workpiece.
DESCRIPTION OF THE PRIOR ART
As is well known among people skilled in the art, a semiconductor wafer dicer, which cuts a semiconductor wafer along cutting lines arranged in a lattice pattern on the surface of the semiconductor wafer, performs the cutting by causing a rotationally driven, thin, disk-like cutting edge to interfere with the semiconductor wafer, and moving the cutting edge and the semiconductor wafer relative to each other along the cutting lines. With such a dicer, swarf formed by the cutting of the semiconductor wafer adheres to the surface of the semiconductor wafer as contamination. Thus, the dicer is also equipped with a cleaning apparatus for removing the contamination from the surface of the semiconductor wafer. This cleaning apparatus includes nozzle means disposed adjacent the cutting edge, and high pressure cleaning liquid feeding means. The nozzle means has an ejection port, and a high pressure cleaning liquid path communicating with the ejection port. The high pressure cleaning liquid feeding means feeds a cleaning liquid, which may be deionized water, to the high pressure cleaning liquid path of the nozzle means at a high pressure of, for example, 40 to 200 kgf/cm
2
. Such a cleaning liquid is jetted at a high pressure from the ejection port of the nozzle means toward the surface in an area of the semiconductor wafer which is cut by the cutting edge. By this measure, the surface of the semiconductor wafer is cleaned; that is, the contamination is removed from the surface of the semiconductor wafer.
The foregoing cleaning apparatus poses the following problems to be solved: It is necessary to dispose a relatively bulky and expensive high pressure cleaning liquid feeding means for feeding a cleaning liquid at a considerably high pressure of, for example, 40 to 200 kgf/cm
2
. It is also necessary that a pipeline between the high pressure cleaning liquid feeding means and the nozzle means be a relatively expensive one resistant to the high pressure cleaning liquid. Thus, not only the apparatus is relatively bulky, but the manufacturing cost for the apparatus is also considerably high.
SUMMARY OF THE INVENTION
A principal object of the present invention is to provide a novel and improved cleaning apparatus which obviates the need to feed a cleaning liquid at a considerably high pressure, and thus is free from the above-described problems facing the conventional cleaning apparatus.
The inventors of the present invention conducted extensive studies and experiments. As a result, they found that if a cleaning liquid is jetted by the action of a compressed gas, nearly the same cleaning effect as obtained by a jet of a considerably high pressure cleaning liquid can be achieved, even when the pressure of the compressed gas is not very high. Even at the pressure of the compressed gas which is much lower than the pressure of the cleaning liquid hitherto employed, a sufficient cleaning effect can be attained. Hence, the cleaning apparatus can be rendered considerably compact and inexpensive compared with the conventional cleaning apparatus. Particularly when the compressed gas is fed at a pressure of 2.7 kgf/cm
2
or higher, and ejected through a constriction with an internal diameter of 0.5 to 3.0 mm, the ejection speed of the compressed gas becomes supersonic. When this ejected gas is caused to act on the cleaning liquid, and jetted, together with the cleaning liquid, at an object to be cleaned, there can be achieved substantially the same cleaning effect as when a considerably high pressure cleaning liquid is jetted at an object to be cleaned.
Thus, according to the present invention, there is provided a cleaning apparatus, which attains the aforementioned principal object, comprising:
nozzle means having an ejection port, a cleaning liquid path communicating with the ejection port, and a compressed gas path communicating with the ejection port;
cleaning liquid feeding means for feeding a cleaning liquid to the cleaning liquid path; and
compressed gas feeding means for feeding a compressed gas to the compressed gas path, wherein
the compressed gas is ejected from the ejection port through the compressed gas path, while the cleaning liquid is ejected from the ejection port through the cleaning liquid path.
Preferably, the compressed gas feeding means feeds the compressed gas to the compressed gas path at a pressure of 2.7 kgf/cm
2
or higher, especially a pressure of 2.7 to 6.0 kgf/cm
2
. In a downstream end portion of the compressed gas path, a constriction is preferably formed. The internal diameter, d, of the constriction is preferably 0.5 to 3.0 mm, especially 1.0 to 2.0 mm. In a referred embodiment, the cleaning liquid path is caused to communicate with the compressed gas path between the constriction and the ejection port, or at the constriction, and is also caused to communicate with the ejection port via the downstream end portion of the compressed gas path. Advantageously, at least a portion of the compressed gas path, ranging from the constriction to the ejection port, extends substantially straightly, and a downstream end portion of the cleaning liquid path extends at an angle of 45 to 90 degrees with the compressed gas path. The cleaning liquid feeding means can feed the cleaning liquid to the cleaning liquid path at a pressure of 1.5 to 2.5 kgf/cm
2
. The cleaning liquid may be deionized water, and the compressed gas may be compressed air.
REFERENCES:
patent: 3577808 (1971-05-01), Visser
patent: 4666083 (1987-05-01), Yie
patent: 4787404 (1988-11-01), Klosterman et al.
patent: 4815241 (1989-03-01), Woodson
patent: 5035090 (1991-07-01), Szucs
patent: 5462605 (1995-10-01), Szucs
patent: 5918817 (1999-07-01), Kanno et al.
Ohkawara Satoshi
Ozawa Naritoshi
Qiu Xiaoming
Disco Corporation
Morris Lesley D.
Smith Gambrell & Russell
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