Polishing pad and polisher
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United States of America Patent
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Apr 8, 2003
Grant Date -
N/A
app pub date -
Feb 15, 2002
filing date -
Aug 27, 1999
priority date (Note) -
Expired
status (Latency Note)
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Abstract
A window member (11) having an intentionally designed distribution of refractive index is used, as a transparent window member in a light transmission area of a polishing pad for detecting the end point of polishing by a CMP method. This window member (11) has areas (11a) having a high refractive index and areas (11b) having a low refractive index in its window face. In a cross section normal to the window face, the high-refractive index areas (11a) and the low-refractive index areas (11b) are alternately arranged in stripes. These areas (11a and 11b) in the window face are in a Fresnel zone plate arrangement in which the first area (center circle) is a bright one (area having a high refractive index). A plurality of such Fresnel zone plates (F) are arrayed in a matrix in the window face of the window member (11).
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