Chemical mechanical polishing pad having a process-dependent groove configuration
View Patent ↗A polishing body, e.g., pad ( 200, 230, 260, 300 ) or belt ( 400, 500 ) having a polishing layer ( 214, 404 ) that includes a backmixing region ( 202, 232, 262, 308, 416, 508 ) wherein backmixing can occur within a slurry ( 116 ) between a wafer ( 204, 234, 264, 304, 408 ), or other article, and the polishing layer under certain conditions. The polishing layer includes a first groove configuration ( 206, 236, 266, 312, 428, 504 ) within the backmixing region and a second grove configuration ( 208, 238, 268, 320, 432, 520 ) outside of the backmixing region that is different from the first groove configuration. The first groove configuration is designed based upon whether or not the presence of spent slurry within the backmixing region is detrimental or beneficial to polishing the wafer.
1. A polishing pad for polishing an article rotated at a predetermined first rotational rate about a first rotational axis, comprising:
(a) a polishing layer operatively configured to be moved at a predetermined rate relative to the first rotational axis, the polishing layer comprising:
(i) a boundary located at 0.5 to 2 times the critical radius calculated as a function of the predetermined first rotational rate of the article and the predetermined rate of the polishing layer, the boundary having a first side and a second side opposite the first side;
(ii) a first set of grooves located on the first side of the boundary and having a first configuration; and
(iii) a second set of grooves located on the second side of the boundary and having a second configuration different from the first configuration.
2. The polishing pad according to claim 1 , wherein at least some of the grooves in the first set of grooves are connected to corresponding respective grooves of the second set of grooves across the boundary.
3. The polishing pad according to claim 1 , wherein the polishing layer is circular in shape and is rotatable about a second rotational axis in a predetermined direction and the predetermined rate of the polishing layer is a predetermined second rotational rate about the second rotational axis.
4. The polishing pad according to claim 3 , wherein the first set of grooves is located proximate the second rotational axis and contains grooves that are substantially tangent to the predetermined direction.
5. The polishing pad according to claim 3 , wherein the first set of grooves is located proximate the second rotational axis and contains grooves that are substantially radial relative to the polishing layer.
6. The polishing pad according to claim 1 , wherein the polishing layer is elongate and the predetermined rate of the polishing layer is a linear velocity.
7. A method of making a polishing pad having a polishing layer for polishing an article rotated at a predetermined first rotational rate about a first rotational axis while the polishing layer is moved at a predetermined rate relative to the first rotational axis, the method comprising the steps of:
(a) determining the location of a boundary on the polishing layer at 0.5 to 2 times the critical radius calculated as a function of the predetermined first rotational rate of the article and the predetermined rate of the polishing layer;
(b) providing a first set of grooves of a first configuration to the polishing layer on a first side of the boundary; and
(c) providing a second set of grooves of a second configuration different from the first configuration on a second side of the boundary opposite the first side.
8. The method according to claim 7 , further including the step of joining at least some of the grooves of the first set of grooves to corresponding respective grooves of the second set of grooves across the boundary.
9. The method according to claim 7 , wherein backmixing of a polishing medium occurs in the first set of grooves.
10. The method according to claim 9 , wherein the step of selecting the first configuration includes selecting the first configuration based on the process being one of a type in which polishing byproducts are beneficial to polishing.