CMP pad having a radially alternating groove segment configuration
View Patent ↗A polishing pad ( 104 ) having an annular polishing track ( 122 ) and including a plurality of grooves ( 148 ) that each traverse the polishing track. Each groove includes a plurality of flow control segments (CS 1 –CS 3 ) and at least two discontinuities in slope (D 1 , D 2 ) located within the polishing track.
1. A polishing pad, comprising:
a) a polishing layer configured for polishing at least one of a magnetic, optical and semiconductor substrate in the presence of a polishing medium, the polishing layer having a rotational center and including an annular polishing track concentric with the rotational center and having a width; and
b) a plurality of grooves, located in the polishing layer, each traversing the entirety of the width of the annular polishing track and including an extrinsic curvature having at least two discontinuities within the annular polishing track, the at least two discontinuities being in opposite directions from one another and providing an increase and decrease in value of the extrinsic curvature, and having a first direction radially inward of the first discontinuity, a second direction in between the first discontinuity and the second discontinuity, and a third direction radially outward of the second discontinuity, and the change in direction between at least one pair of adjacent directions is from −85 degrees to 85 degrees.
2. The polishing pad according to claim 1 , wherein the at least two discontinuities of each of the grooves partition that groove so as to have an inner edge flow control segment, an outer edge flow control segment and at least one intermediate flow control segment located between the inner edge flow control segment and the outer edge flow control segment.
3. The polishing pad according to claim 2 , wherein the inner edge flow control segment has a first orientation and a first curvature and the outer edge flow control segment has a second orientation and a second curvature each the same as the first orientation and the first curvature.
4. The polishing pad according to claim 3 , wherein each of the first and second orientations is radial.
5. The polishing pad according to claim 3 , wherein each of the first and second curvatures is zero.
6. The polishing pad according to claim 1 , wherein each of the grooves has at least three discontinuities in curvature and wherein adjacent ones of the at least three discontinuities are in opposite directions from one another.
7. The polishing pad according to claim 1 , wherein the annular polishing track has a circular inner boundary and a circular outer boundary spaced apart by the width, each of the grooves having an inner edge flow control segment that crosses the inner boundary and an outer edge flow control segment that crosses the outer boundary.
8. The polishing pad according to claim 1 , wherein N represents a number and each groove has N discontinuities, N transitions occurring at the N discontinuities, and N+1 flow control segments located alternatingly with the N transitions, each of the N transitions having a width no greater than the width of the polishing track divided by 2N.
9. The polishing pad according to claim 8 , wherein the width of each of the N transitions is no greater than the width of the polishing track divided by 4N.
10. A method of polishing at least one of a magnetic, optical and semiconductor substrate in the presence of a polishing medium, including:
a) polishing with a polishing pad, the polishing pad comprising: i) a polishing layer configured for polishing at least one of a magnetic, optical and semiconductor substrate in the presence of a polishing medium, the polishing layer having a rotational center and including an annular polishing track concentric with the rotational center and having a width, the annular track having at least three flow control zones; and ii) a plurality of grooves, located in the polishing layer, each traversing the entirety of the width of the annular polishing track and including an extrinsic curvature having at least two discontinuities within the annular polishing track, the at least two discontinuities being in opposite directions from one another and providing an increase and decrease in value of the extrinsic curvature, and having a first direction radially inward of the first discontinuity, a second direction in between the first discontinuity and the second discontinuity, and a third direction radially outward of the second discontinuity, and the change in direction between at least one pair of adjacent directions is from −85 degrees to 85 degrees; and
b) adjusting removal rate of the substrate with each of the at least three flow control zones.