Variable pressure plate CMP carrier

In an equipment used to polish a planar article having a frontside surface and a backside surface in which the article is lifted by said backside surface and placed upon a rotating polishing pad for polishing said frontside surface, a method for removably positioning said article for polishing, comprising the steps of:

• providing a rotating member having a major lower surface with a plurality of recesses each with a conduit path radially leading to a smaller circular pattern of portholes disposed near the center of said rotating member, said recesses arranged in concentric segments;
• a nozzle plate covering said major lower surface defining a plurality of chambers therebetween, said nozzle plate providing radial patterns of gas dispensing orifices aligned centrally relative each chamber, wherein a preset regulated gas pressure communicating to each orifice pattern exerts a preset opposing force against a force urging said wafer onto said polishing pad;
• at least two of said orifice patterns having its gas pressure adjusted independently from one another such that independent pressure control permit varying forces to be exerted against the back side of said wafer;
• a ring secured to the major lower surface of said rotating member adapted to centrally position and partially recess the back side of said wafer, said major lower surface is oriented substantially parallel to said upper surface of said rotating polishing pad, said rotatable polishing head assembly has a rotatable axis which is parallel and offset relative to a 9 rotatable axis of said polishing pad;
• a spindle shaft, with a first end fixidly attached to the top surface of said rotating member, said first end of spindle shaft having a plurality of longitudinal conduits machined at progressive depth intervals, said longitudinal conduit form a small circular pattern at said first end aligning with porthole pattern in said rotating member, said longitudinal conduits each communicate with an external groove via a port that intersecting a depth matching conduit, and
• a stationary journal bearing having a plurality of gas supply ports which are separated longitudinally to align with said external grooves in said spindle shaft.