Abrading – Abrading process – Glass or stone abrading
Reexamination Certificate
2001-10-09
2002-08-20
Hail, III, Joseph J. (Department: 3723)
Abrading
Abrading process
Glass or stone abrading
C451S288000, C451S028000, C451S262000
Reexamination Certificate
active
06435948
ABSTRACT:
BACKGROUND OF INVENTION
Chemical mechanical polishing (CMP) is generally known in the art. For example U.S. Pat. No. 5,177,908 issued to Tuttle in 1993 describes a finishing element for semiconductor wafers, having a face shaped to provide a constant, or nearly constant, surface contact rate to a workpiece such as a semiconductor wafer in order to effect improved planarity of the workpiece. U.S. Pat. No. 5,234,867 to Schultz et al. issued in 1993 describes an apparatus for planarizing semiconductor wafers which in a preferred form includes a rotatable platen for polishing a surface of the semiconductor wafer and a motor for rotating the platen and a non-circular pad is mounted atop the platen to engage and polish the surface of the semiconductor wafer. Fixed abrasive finishing elements are known for polishing. Illustrative examples include U.S. Pat. No. 4,966,245 to Callinan, U.S. Pat. No. 5,823,855 to Robinson, and WO 98/06541 to Rutherford.
An objective of polishing of semiconductor layers is to make the semiconductor layers as nearly perfect as possible.
BRIEF SUMMARY OF INVENTION
Current finishing elements and equipment can suffer from being costly to manufacture. Generally very complex mechanical equipment used when finishing semiconductor wafers. Complex, expensive, and bulky mechanical drives are generally used for generating polishing pad and wafer polishing motions. Also current finishing elements for semiconductor wafers generally have coextensive surface layers which can limit their versatility in some demanding finishing applications. Current polishing pads are generally larger than the workpiece being finished which consumes precious floor space in a semiconductor fab. Still further, current finishing apparatus are not capable of supplying a parallel finishing motion to finishing elements solely through magnetic coupling forces. Still further, current finishing apparatus are not capable of supplying multiple different parallel finishing motions to multiple finishing elements solely through magnetic coupling forces. Still further, current finishing apparatus are not capable of supplying multiple different parallel finishing motions to multiple different finishing elements solely through magnetic coupling forces. Still further, a lack of the above characteristics in a finishing element reduces the versatility of the finishing method which can be employed for semiconductor wafer surface finishing. Still further, current finishing pads can be limited in the way they apply pressure to the abrasives and in turn against the semiconductor wafer surface being finished. These unwanted effects are particularly important and can be deleterious to yield and cost of manufacture when manufacturing electronic wafers which require extremely close tolerances in required planarity and feature sizes.
It is an advantage of this invention to improve the finishing method for semiconductor wafer. surfaces to make them as perfect as possible. It is an advantage of this invention to make finishing elements and equipment with a lower cost of manufacture and reduce the mechanical complexity of the finishing equipment and thus also reduce the cost of finishing a semiconductor wafer surface. It is a preferred advantage of this invention to develop finishing apparatus and finishing elements that can be smaller than the workpiece being finished. It is further an advantage of the invention to develop finishing apparatus that are capable of supplying a parallel finishing motion to finishing elements solely through magnetic coupling forces. It is further an advantage of the invention to develop current finishing apparatus that are capable of supplying multiple different parallel finishing motions to multiple different finishing elements solely through magnetic coupling forces. It is an advantage of the invention to develop a finishing element which has a unique way of applying pressure to the unitary and/or a plurality of discrete finishing surface(s) and to the workpiece surface being finished. It is further an advantage of this invention to help improve yield and lower the cost of manufacture for finishing of workpieces having extremely close tolerances such as semiconductor wafers.
A preferred embodiment of this invention is directed to a method for finishing a semiconductor wafer surface comprising a step 1) of providing a magnetically responsive finishing element free of a nonmagnetic driving mechanism; a step 2) of providing a magnetic driving element operatively connected to a driving mechanism; a step 3) of providing a semiconductor wafer surface between the magnetically responsive finishing element and the magnetic driving element; a step 4) of magnetically coupling the magnetically responsive finishing element with the magnetic driving element; and a step 5) of applying an parallel operative finishing motion in the operative finishing interface formed between the semiconductor wafer surface and the magnetically responsive finishing element by moving magnetic driving element with the driving mechanism.
A preferred embodiment of this invention is directed to a method for finishing a semiconductor wafer surface comprising a step 1 of providing a plurality of magnetically responsive finishing elements free of any physically connected movement mechanism; a step 2) of providing a plurality of magnetic driving elements operatively connected to at least one driving mechanism; a step 3) of providing a semiconductor wafer surface between the plurality of magnetically responsive finishing elements and the plurality of the magnetic driving elements; a step 4) of magnetically coupling the magnetically responsive finishing elements with the plurality of the magnetic driving elements; and a step 6) of applying an parallel operative finishing motion in the operative finishing interface formed between the semiconductor wafer surface and the plurality of the magnetically responsive finishing elements by moving the plurality of the magnetic driving elements with at least one driving mechanism.
A preferred embodiment of this invention is directed to a method of removing unwanted material from a semiconductor wafer surface comprising a step 1) of providing a magnetically responsive finishing element having a finishing surface free of any physically connected movement mechanism; a step 2) of providing a magnetic driving element having a driving mechanism; a step 3) of positioning the semiconductor wafer being finished with a holder proximate to the magnetically responsive finishing element and between the magnetically responsive finishing element and magnetic driving element; a step 4) of applying an operative finishing motion comprising a magnetically induced parallel operative finishing motion in the interface between the semiconductor wafer surface being finished and the finishing surface of the magnetically responsive finishing element in order to remove the unwanted material.
A preferred embodiment of this invention is directed to a method of finishing a semiconductor wafer having a finishing cycle time comprising a step 1) of providing a plurality of magnetically responsive finishing elements having a finishing surface free of any nonmagnetic driving mechanism; a step 2) of providing a plurality of magnetic driving elements having at least one driving mechanism; a step 3) of providing a control subsystem having at least one semiconductor wafer finishing sensor for providing finishing information; a step 4) of positioning the semiconductor wafer being finished with a holder proximate to the plurality of the magnetic finishing elements and between the magnetically responsive finishing element and the plurality of the magnetic driving elements; a step 5) of applying an operative finishing motion comprising a magnetically induced parallel finishing motion between the semiconductor wafer surface being finished and the finishing surfaces of the plurality of the magnetically responsive finishing elements; and a step 6) of controlling in situ a control parameter with the finishing control subsystem after evalua
Beaver Creek Concepts Inc
Hail III Joseph J.
Thomas David B.
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