Planarization after metal chemical mechanical polishing in semiconductor wafer fabrication

A process for planarization of an insulation layer disposed on a semiconductor wafer and having a surface containing a downwardly stepped chemically mechanically polished arrangement of metal lines in corresponding trenches defined in the insulation layer between intervening insulation portions;

• including a first pattern portion of metal lines separated by intervening insulation portions and defining a first pattern factor having a first value, an adjacent second pattern portion of metal lines separated by intervening insulation portions and defining a second pattern factor having a second value different from the first value, and an adjacent third pattern portion of metal lines separated by intervening insulation portions and defining a third pattern factor having a third value different from the first and second values;
• the second pattern portion being located at a step depth relative to the insulation layer surface different from the step depth of the first pattern portion relative to said layer surface, and the third pattern portion being located at a step depth relative to the insulation layer surface different from the step depths of the first and second pattern portions relative to said layer surface;
• the process comprising chemically mechanically polishing the insulation layer surface and the first, second and third pattern portions sufficiently to reduce the step depths of the first, second and third pattern portions relative to the insulation layer surface and relative to each other, for planarization of the insulation layer surface and first, second and third pattern portions relative to each other.

A process for planarization of an insulation layer disposed on a semiconductor wafer and having a surface containing a downwardly stepped chemically mechanically polished arrangement of metal lines in corresponding trenches defined in the insulation layer between intervening insulation portions;

• including a first pattern portion of metal lines separated by intervening insulation portions and defining a first pattern factor having a first value, an adjacent second pattern portion of metal lines separated by intervening insulation portions and defining a second pattern factor having a second value smaller than the first value, and an adjacent third pattern portion of metal lines separated by intervening insulation portions and defining a third pattern factor having a third value smaller than the second value;
• the second pattern portion being located at a step depth relative to the insulation layer surface smaller than the step depth of the first pattern portion relative to said layer surface, and the third pattern portion being located at a step depth relative to said layer surface smaller than the step depth of the second pattern portion relative to said layer surface;
• the process comprising chemically mechanically polishing the insulation layer surface and the first, second and third pattern portions sufficiently to reduce the step depths of the first, second and third pattern portions relative to the insulation layer surface and relative to each other, for planarization of the insulation layer surface and first, second and third pattern portions relative to each other.