CMP polishing pad having grooves arranged to improve polishing medium utilization
View Patent ↗A polishing pad ( 104, 304, 404, 504 ) having an annular polishing track ( 152, 312, 412, 512 ) for polishing a wafer ( 120, 316, 416, 516 ). A plurality of grooves ( 112, 320, 420, 520 ) are arranged within the wafer track so that they are spaced from one another both radially and circumferentially relative to the rotational nature of pad and are at least partially non-circumferential relative to the pad.
1. A polishing pad, comprising:
a) a polishing layer configured to polish a surface of at least one of a magnetic, optical or semiconductor substrate in the presence of a polishing medium, the polishing layer including a rotational axis, an outer periphery and an annular polishing track concentric with the rotational axis; and
b) a plurality of grooves formed in the polishing layer and comprising a first set of grooves located entirely within the annular polishing track, each groove in the first set of grooves:
i) being spaced from other grooves in the first set of grooves in a radial direction relative to the rotational axis;
ii) being spaced from other grooves in the first set of grooves in a circumferential direction relative to the polishing pad; and
iii) having a longitudinal axis at least a portion of which is oriented non-circumferentially relative to the polishing pad forming a discontinuous flow for the polishing medium where land regions interrupt flow to the outer periphery.
2. The polishing pad according to claim 1 , wherein the surface of the substrate has a rotational center and includes a least dimension along a line extending through the rotational center, each groove in the first set of grooves having a first end and a second end spaced from the first end by a distance less than the least dimension of the surface.
3. The polishing pad according to claim 1 , wherein the plurality of grooves are arranged in a plurality of groups each containing ones of the plurality of grooves arranged end-to-end along a smooth path.
4. The polishing pad according to claim 3 , wherein each of the plurality of grooves is curved.
5. The polishing pad according to claim 1 , wherein said polishing layer further comprises a peripheral region extending between the annular polishing track and the outer periphery, the plurality of grooves further comprising a second set of grooves each of which is present only in the annular polishing track and the peripheral region.
6. The polishing pad according to claim 1 , wherein the annular polishing track has an inner periphery defining a central region of the polishing layer, the plurality of grooves further comprising a third set of grooves each of which is present only in the annular polishing track and the central region.
7. A polishing pad, comprising:
a) a polishing layer configured to polish a surface of at least one of a magnetic, optical or semiconductor substrate in the presence of a polishing medium, the polishing layer including:
i) a rotational axis;
ii) an outer periphery;
iii) an annular polishing track concentric with the rotational axis; and
iv) a peripheral region located between the annular polishing track and the outer periphery; and
b) a plurality of grooves formed in the polishing layer and comprising:
i) a first set of grooves located entirely within the annular polishing track, each of at least some of the grooves in the first set of grooves:
A) spaced from others of the grooves in the first set of grooves in a radial direction relative to the rotational axis of the polishing layer; and
B) spaced from others of the grooves in the first set of grooves in a circumferential direction relative to the polishing pad; and
ii) a second set of grooves each located only in the annular polishing track and the peripheral region forming a discontinuous flow for the polishing medium where land regions interrupt flow to the outer periphery.
8. The polishing pad according to claim 7 , wherein the polishing track further includes an inner periphery, the polishing layer further including:
a) a central region concentric with the rotational axis and defined by the inner periphery of the annular polishing track; and
b) a third set of grooves each located only in the central region and the annular polishing track.
9. The polishing pad according to claim 7 , wherein each groove in the first set of grooves has a longitudinal axis at least a portion of which is oriented non-circumferentially relative to the polishing pad.
10. The polishing pad according to claim 7 , wherein the plurality of grooves are arranged in a plurality of groups each containing ones of the plurality of grooves arranged end-to-end along a smooth path.