Tool changing – Process
Reexamination Certificate
2001-03-07
2003-02-18
Briggs, William (Department: 3722)
Tool changing
Process
C451S342000, C483S031000, C483S033000, C483S036000, C483S038000
Reexamination Certificate
active
06520895
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention concerns a semiconductor flattening and polishing device which can be applied to processes for manufacturing semiconductor devices such as ultra-high-density integrated circuits (ULSIs), and more specifically, it concerns a protocol for exchanging polishing pad components in such a flattening and polishing operation.
2. Description of the Background
There are known polishing devices wherein wafers are polished or CMP-polished by using a polishing pad component which is axially supported on a spindle axle and by pressing a wafer which is retained by a chuck from above while a polishing material slurry is fed onto its pad plane and while the pad and wafer are rotated concurrently or countercurrently (see Japanese Patent Application Publication No. Kokai Hei 6[1994]-21028, Hei 7[1995]-266219, Hei 8[1996]-192353, and Hei 8[1996]-293477).
Hard foamy urethane sheets, polyester fiber non-woven cloths, felts, polyvinyl alcohol fiber non-woven cloths, nylon fiber non-woven cloths, and ones obtained by flowing foamable urethane resin solutions on these non-woven cloths and by subsequently foaming and curing them are used as pads (polishers) to be integrated with such polishing devices.
When a wafer is polished by using any of the aforementioned polishing devices, its pad becomes worn as a result of polishing, and therefore, the pad is subjected to dressing and washing operations by using a pad conditioning device after one or multiple wafers have been polished for the purpose of roughening (repairing) the pad. Concrete examples of heretofore proposed pad conditioning devices which serve such pad roughening functions include the combination of a dressing disc and a washing solution, high-pressure washing solution spray nozzles (see Japanese Patent Application Publication No. Kokai Hei 3[1991]-10769, Hei 10[1998]-202502, Hei 10[1998]-235549, and Hei 10[1998]-244459), combination of a dressing disc and a washing brush (see Japanese Patent Application Publication No. Kokai Hei 10[1998]-244458), and the combination of a cup hold-type dressing whetstone, a compressive washing solution spray nozzle, and a washing brush (see Japanese Patent Application Publication No. Kokai Hei 10[1998]-244458).
Polishing pad components are thus conditioned repeatedly, and once a polishing pad component reaches its wear limit, it is exchanged with a new polishing pad component. Such a polishing pad component is obtained by pasting a polishing cloth or polyurethane sheet (referred to as a “pad,” “polishing cloth,” or “polisher”) onto an aluminum or stainless steel attachment panel (polisher supporter), and such a polishing cloth is reloaded manually by an operator. The peeling of the polishing cloth and its pasting onto the attachment panel, however, are cumbersome during such a polishing cloth reloading operation, and furthermore, advanced skills are required, as a result of which the utilization efficiency of the polishing device decreases. It is in such a context that this method is replaced by one wherein a new polishing pad component which has been obtained by preliminarily pasting an unused polishing cloth onto an attachment panel is prepared and wherein a used and worn polishing pad component is exchanged with this new polishing pad component.
Even in such a method, however, a manual operation wherein a worker enters the polishing device in person is unavoidable, and cumbersome bolt attachment and detachment procedures are required for exchanging polishing pad components. It is in such a context that devices for automatically exchanging polishing pad components have been proposed, for example, by Japanese Patent Application Publication No. Kokai Hei 8[1996]-174406 and Hei 10[1998]-230449. In such a case, however, a polishing pad component is above a disc, the diameter of which is large and wherein a wafer, the plane of which to be polished faces downward, is polished while said wafer is pressed from above onto the pad plane of the polishing pad component. For this reason, the diameter of the disc (as well as of the polishing pad component) is large in comparison with the wafer diameter, as a result of which the structure of the automatic exchange device for exchanging such large polishing pad components becomes large and complicated, accompanied by high production costs.
Regarding the polishing devices mentioned in the aforementioned patent publications (CMP devices), furthermore, the planes of wafers to be polished face downward, and therefore the end point of the polishing operation may be estimated by decoding the variations of voltages or currents for rotating and driving the polishing pad component, wafer, etc., or the end point of the polishing operation may alternatively be estimated by configuring a laser beam transmission window on a disc and by monitoring the wafer polishing state while a laser beam is irradiated onto the plane of the wafer to be polished which is polished (see Japanese Patent Application Publication No. Kokai Hei 6[1994]-216095, Hei 8[1996]-172118, Hei 9[1997]-262743, and Hei 10[1998]-199951).
SUMMARY OF THE INVENTION
In contrast with these CMP devices, a CMP device wherein a wafer, the plane of which to be polished faces upward, is retained by the suction of a wafer chuck mechanism on an index table, wherein a polishing pad component which is axially supported on a spindle axle which is positioned above the wafer is pressed onto the wafer from above while its pad plane faces downward, and wherein the wafer is polished by rotating said wafer and polishing pad component has been proposed and put to practical uses (see Japanese Patent Application Publication No. Kokai Hei 10[1998]-303152 and Hei 11[1999]-156711). The polishing pad diameter of such a CMP device is small in comparison with the wafer diameter, and since the plane to be polished faces upward, it is easy to measure the film thickness during the polishing operation or to judge the end of the polishing operation. Since the diameter of the polishing pad component is smaller than those of the polishing pad components of the known CMP devices, furthermore, the exchange operation can be advantageously facilitated.
Such a CMP device wherein the polisher diameter is small in comparison with the wafer diameter, however, is characterized by a high utilization efficiency of the polishing plane (pad plane) of the polisher (polishing pad component), and accordingly, the depressions of the polishing plane of the polisher tend to become congested. It is necessary to increase the dressing frequency of such a CMP device for the purpose of maintaining the required polishing performances, but since the dressing is synonymous with the shaving of the polisher surface, the life of the polisher itself becomes shortened, as a result of which the period between operations for exchanging polishing pad components become shorter, and the exchange frequency increases. As has been mentioned above, furthermore, the polishing pad component is attached to the spindle axle while its pad plane faces downward, as a result of which it becomes difficult to achieve a favorable precision during the exchange operation, and the operative efficiency is problematically unfavorable.
An object of the present invention, which has been conceived in response to the foregoing problems, is to provide a polishing pad component exchange device and a corresponding method which are capable of automating polishing pad component exchange operations and of improving the polishing pad component exchanging operative efficiency. In order to solve the aforementioned problems, the polishing device of the present invention may, for example, be comprised of an object retention mechanism (e.g., wafer chuck mechanism of application embodiments) which retains an object to be polished (e.g., wafer of application embodiments) while it
Ide Satoru
Kobayashi Kazuo
Senga Tatsuya
Tanaka Kiyoshi
Briggs William
Nikon Corporation
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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