Semiconductor wafer for improved chemical-mechanical polishing over large area features

A semiconductor wafer used in mechanical and/or chemical-mechanical planarizing of metal layers, comprising:

• a substrate having an upper surface;
• a separation layer on the substrate, the separation layer having a top surface and a cavity having sidewalls extending from the top surface towards the upper surface of the substrate;
• a large area feature on a floor of the cavity, the large area feature having a plurality of raised features projecting upwardly from the floor into the cavity;
• a support structure in the cavity, the support structure having a crown proximate to a plane defined by the top surface of the separation layer, and the support structure having a first section extending in a first direction across substantially one portion of the cavity and a second section extending in a second direction normal to the first direction across substantially another portion of the cavity;
• and
• a metal conformal layer in the cavity having an upper surface that conforms to a topography of the raised features, wherein the sidewalls of the cavity, the support structure, and the upper surface of the conformal metal layer define a void over the large area feature.

A microelectronic substrate structure for enhancing the performance of mechanical and/or chemical-mechanical planarizing processes comprising:

• a substrate having an upper surface;
• a separation layer on the substrate, the separation layer having a top surface;
• a cavity in the separation layer, the cavity having sidewalls extending from the top surface of the separation layer towards the upper surface of the substrate and a floor;
• a large area feature on the floor of the cavity, the large area feature having a plurality of raised features projecting upwardly from the floor into the cavity;
• a pillar in the cavity, the pillar having a crown proximate to a plane defamed by the top surface of the separation layer;
• and
• an upper layer on the separation layer and in the cavity, wherein a portion of the upper layer closely follows the contour of the raised features projecting upwardly from the floor of the cavity so that a stepper can scan the topography of the raised features, and wherein another portion of the upper layer is on the crown of the pillar.