Polishing pad with grooves to retain slurry on the pad texture
View Patent ↗A rotational chemical mechanical polishing pad designed for use with a polishing medium. The polishing pad includes a polishing layer having a polishing surface containing a plurality of grooves. At least a portion of each of the plurality of grooves has a shape and orientation determined as a function of the trajectory of the polishing medium during use of the pad.
1. A polishing pad for use in conjunction with a polishing medium having an ideal trajectory imparted by the rotation of the polishing pad during use, the 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 including a circular polishing surface having an annular polishing track during polishing; and
(b) at least one groove formed in the polishing layer and having an orthogonal portion located within the polishing track, the orthogonal portion having a length and being shaped along the entire length to be orthogonal to the trajectory angle θ of the ideal fluid trajectory along the orthogonal portion.
2. The polishing pad according to claim 1 , wherein the polishing track has a width and the orthogonal portion traverses at least 50% of the width.
3. The polishing pad according to claim 2 , wherein the orthogonal portion traverses at least 75% of the width of the polishing track.
4. The polishing pad according to claim 1 , comprising a plurality of grooves partially defined by repeating the orthogonal portion circumferentially around the polishing surface.
5. The polishing pad according to claim 4 , wherein the plurality of grooves are partially defined by repeating the orthogonal portion circumferentially around the polishing surface at a constant angular pitch.
6. The polishing pad according to claim 1 , wherein the shape of the orthogonal portion is defined by the equation
r
*
=
r
O
ⅇ
1
2
(
3
θ
)
3
/
2
where r o is the initial radial position from a concentric center of the polishing pad and θ is the trajectory angle.
7. 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; and
(b) at least one groove formed in the polishing layer and having an orthogonal portion located within the polishing track, the orthogonal portion having a length and being shaped in accordance with the equation
r
*
=
r
O
ⅇ
1
2
(
3
θ
)
3
/
2
where r o is the initial radial position from a concentric center of the polishing pad and θ is the trajectory angle.
8. The polishing pad according to claim 7 , wherein the polishing surface includes, during polishing, a polishing track having a width, the orthogonal portion traversing at least 50% of the width.
9. The polishing pad according to claim 7 , comprising a plurality of grooves partially defined by repeating the orthogonal portion circumferentially around the polishing surface at a constant angular pitch.