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US 5,733,182 AGranted
Ultra flat polishing
AssigneeFujitsu Limited
InventorsTomoaki Muramatsu, Takashi Yoshida
Life of this patent
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AssigneeFujitsu Limited
InventorsTomoaki Muramatsu, Takashi Yoshida
Estimating the term…
A polishing apparatus comprises a pressure container having a first opening at its bottom and being rotatable about an axis perpendicular to a plane of the first opening; a wafer support coupled elastically to the first opening, sealing the first opening hermetically and having a wafer supporting surface; and a lower surface plate disposed underneath the wafer supporting surface and having a polishing surface approximately parallel to the wafer supporting surface. The wafer support may be provided with flatness adjusting means for selectively applying a larger pressure on a region of the wafer held on the wafer supporting surface than a pressure on other region. The flatness adjusting means may comprise a plurality of pressing pins, or may comprise a hollow within the wafer support, a surface plate having elasticity and sealing the hollow, and means for applying pressure to the hollow. Wafer can be polished under uniform pressure applied on the back surface. Flatness of the wafer can be improved.
A polishing apparatus comprising:
A method of polishing a wafer by pressing a surface of the wafer to be polished to a polishing surface and moving said surface to be polished and said polishing surface elatively, comprising the step of polishing while selectively applying a first pressure on one part of said wafer a second pressure on another part, the first pressure being larger than the second by a selected amount.
A method of polishing a wafer by pressing a surface of the wafer to be polished to a polishing surface and moving said surface to be polished and said polishing surface relatively, comprising the step of polishing while selectively applying different pressures to a plate formed of an elastic material on a back surface of a wafer to be polished.
A method of polishing a wafer by pressing a surface of the wafer to be polished to a polishing surface and moving said surface to be polished and said polishing surface relatively, comprising the steps of
Dependencies are inferred from the claim text.