Abrading – Machine – Combined
Reexamination Certificate
1999-11-09
2001-09-25
Hail, III, Joseph J. (Department: 3723)
Abrading
Machine
Combined
C451S287000, C451S288000, C451S289000, C451S066000, C451S062000
Reexamination Certificate
active
06293855
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a polishing apparatus, and more particularly to a polishing apparatus for polishing a workpiece such as a semiconductor wafer to a flat mirror finish.
BACKGROUND ART
Recent rapid progress in semiconductor device integration demands smaller and smaller wiring patterns or interconnections and also narrower spaces between interconnections which connect active areas. If a photolithographic process is used to form circuits, then since the depth of focus of the optical system is relatively small, the focused surface of a stepper requires a high level of flatness. One of the available processes for planarizing surfaces of semiconductor wafers is a chemical mechanical polishing (CMP) conducted by a polishing apparatus in which while supplying an abrasive liquid containing abrasive particles to a polishing cloth mounted on a rotating turntable, the semiconductor wafer held by a carrier is pressed against the polishing cloth and polished thereby.
There has been proposed a polishing apparatus having a processing section such as a polishing section accommodated in a housing so that the polishing apparatus can be installed in a clean room. In this kind of apparatus, a semiconductor wafer is taken out from a wafer cassette mounting section in which a wafer cassette is mounted, transported to a polishing section and polished therein, and the polished semiconductor wafer is cleaned by a cleaning section, and then returned to the wafer cassette in the wafer cassette mounting section.
In the above conventional polishing apparatus, the wafer cassette mounting section for mounting wafer cassettes and the processing section such as a polishing section and a cleaning section are not separated from each other, but are kept in the same environment. Therefore, the cleanliness of the processing section is enhanced to prevent semiconductor wafers in the wafer cassettes, before and after being processed, from being contaminated by the processing section. As a result, the cleanliness of the processing section is required to be higher than necessary, thus increasing the operating cost of the polishing apparatus, and the cleanliness of the semiconductor wafers in the wafer cassettes depends on the cleanliness of the processing section.
In the above conventional polishing apparatus, furthermore, after a semiconductor wafer is processed, e.g., polished, cleaned, a reference position indicated by an orientation flat or a notch of the semiconductor wafer is positioned in alignment with a predetermined direction in a separate process by a dedicated machine. Therefore, it is necessary to incorporate the separate process for positioning semiconductor wafers in the semiconductor fabrication process, and the dedicated machine for positioning semiconductor wafers is required.
DISCLOSURE OF INVENTION
The present invention has been made in view of the above problems. It is a first object of the present invention to provide a polishing apparatus having an independent chamber defined by a partition with a shutter and disposed between a processing section including a polishing section, a cleaning section and the like and a receiving section including wafer cassette units, the independent chamber having an increased level of cleanliness for preventing contamination from being introduced from the processing section into the receiving section.
A second object of the present invention is to provide a polishing apparatus capable of positioning a semiconductor wafer by aligning a reference position (such as an orientation flat or a notch) of the semiconductor wafer with a predetermined direction during a transpotation process in a polishing apparatus.
To achieve the first object described above, according to a first aspect of the present invention, there is provided a polishing apparatus for polishing a workpiece such as a semiconductor wafer, comprising: a processing section for polishing a workpiece; a receiving section for supplying a workpiece to be polished to said processing section and/or receiving a polished workpiece; and a clean chamber disposed between said processing section and said receiving section and defined by a partition with a shutter which separates said section and said receiving section from each other. The receiving section serves to supply a workpiece to be polished to the processing section, or receive a polished workpiece, or supply a workpiece to be polished to the processing section and receive a polished workpiece.
In the first aspect of the present invention, contaminants in the processing section are prevented from reaching the receiving section such as a wafer cassette unit, and hence cleanliness of the processing section is not required to be enhanced to an unnecessarily high level, and the receiving section may be kept clean.
To achieve the second object described above, according to a second aspect of the present invention, there is provided a polishing apparatus for polishing a semiconductor wafer, comprising: a processing section for polishing a semiconductor wafer; a receiving section for supplying a semiconductor wafer to be polished to said processing section and receiving a polished semiconductor wafer; and a positioning mechanism disposed between said processing section and said receiving section, for aligning a reference position of the semiconductor wafer with a predetermined direction while the semiconductor wafer is transported between said processing section and said receiving section.
In the second aspect of the present invention, a semiconductor wafer can be positioned by aligning a reference position (such as an orientation flat or a notch) of the semiconductor wafer with a predetermined direction during the transportation process between the processing section and the receiving section in the polishing apparatus.
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U.S. patent application Ser. No. 09/358,252 filed Jul. 20, 1999 (pending).
Sekimoto Masahiko
Yoshida Masao
Ebara Corporation
Hail III Joseph J.
Nguyen George
Wenderoth , Lind & Ponack, L.L.P.
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