Polishing pad with improved fluidity of slurry and process for preparing same
Provided is a polishing pad that comprises a plurality of first grooves that have a shape of geometric figures that share a center; and a plurality of second grooves that radially extend from the center to the outer perimeter, wherein the depth of the second grooves is equal to, or deeper than, the depth of the first grooves. It is possible for the polishing pad to rapidly discharge any debris generated during the polishing process to reduce such defects as scratches on the surface of a wafer.
1. A polishing pad, which comprises a polishing layer,
wherein the polishing layer comprises, on the polishing surface thereof,
a plurality of first grooves that have a same geometric shape and share a common center; and
a plurality of second grooves that radially extend from the center to the outer periphery,
wherein the depth of the second grooves is 125% to 150% of the depth of the first grooves,
wherein the width of the second grooves is 50% to 200% of the width of the first grooves,
wherein the first grooves and the second grooves each comprise an inner surface perpendicular to the polishing surface and a bottom surface parallel to the polishing surface,
wherein the polishing layer comprises a rounded portion which has a radius of curvature of 0.1 mm to 5 mm and which is machined as a curved surface at an edge at which the polishing surface meets the inner surface.
2. The polishing pad of claim 1 , wherein the depth of the second grooves is 90% or less of the thickness of the polishing layer.
3. The polishing pad of claim 1 , wherein the width of the second grooves is 100% to 200% of the width of the first grooves.
4. The polishing pad of claim 1 , wherein the width of the second grooves is 0.2 mm to 2 mm, and the depth of the second grooves is 0.4 mm to 4 mm.
5. The polishing pad of claim 1 , which has 5 to 15 of the second grooves spaced apart from each other at a certain angle.
6. The polishing pad of claim 5 , which has the first grooves at a pitch spacing of 1 mm to 10 mm.
7. A process for preparing a polishing pad, which comprises:
(1) preparing a polishing layer;
(2) forming a plurality of first grooves on the polishing surface of the polishing layer, the first grooves having a same geometric shape and sharing a common center; and
(3) forming a plurality of second grooves on the polishing surface of the polishing layer, the second grooves radially extending from the center to the outer periphery,
wherein the depth of the second grooves is 125% to 150% of the depth of the first grooves,
wherein the width of the second grooves is 50% to 200% of the width of the first grooves,
wherein the first grooves and the second grooves each comprise an inner surface perpendicular to the polishing surface and a bottom surface parallel to the polishing surface,
wherein the polishing pad comprises a rounded portion machined as a curved surface at an edge at which the polishing surface meets the inner surface, and
wherein the rounded portion has a radius of curvature of 0.1 mm to 5 mm.
8. The process for preparing a polishing pad of claim 7 , wherein the formation of the first grooves and the second grooves is carried out by cutting and removing a part of the polishing surface.
9. The process for preparing a polishing pad of claim 8 , wherein the cutting is carried out using a tip.
10. The process for preparing a polishing pad of claim 8 , wherein the formation of the first grooves and the second grooves comprises forming an inner surface perpendicular to the polishing surface and a bottom surface parallel to the polishing surface by the cutting.
11. The process for preparing a polishing pad of claim 10 , which further comprises, after the formation of the first grooves and the second grooves, machining an edge at which the polishing surface meets the inner surface into a curved surface.