US 5,643,061 A · Pneumatic polishing head for CMP apparatus

Abstract

A polishing head for chemical-mechanical polishing apparatus includes a carrier plate having concentric, integral, cylindrical walls, an annular piston fitting within the outer of the cylindrical walls and a second piston fitting within the inner cylindrical wall and engaging the annular piston. Each piston defines a chamber with the carrier plate and the chambers are isolated from each other by a seal. Pneumatic fittings supply air or vacuum to each chamber. The second piston includes a cylindrical side wall and an integral bottom plate. The bottom plate is thicker in the center than at the side wall and the underside of the plate is covered with a wafer adhering layer. A retaining ring is attached to the lower edge of the annular piston. The retaining ring includes a peripheral groove for separating an outwardly extending flange from the main body of the ring. The underside of the ring includes one or more spiral grooves for circulating slurry about a wafer during polishing.

Claims20

Dependent claims

Chemical-mechanical polishing apparatus including a slurry coated polishing pad and a polishing head for receiving a semiconductor wafer and for holding the wafer against the polishing pad, wherein said polishing head comprises:

a carrier plate having an inner cylindrical wall and an outer cylindrical wall, said walls being concentric and having a common axis;
a first piston fitting within and engaging said outer cylindrical wall and defining a first chamber between said carrier plate and said first piston, said first piston movable in a direction parallel to said axis and having a lower edge;
a second piston fitting within and engaging said inner cylindrical wall, said second piston movable in a direction parallel to said axis and defining a second chamber, separate from said first chamber;
a retaining ring attached to the lower edge of said first piston and surrounding said second piston;
a first pneumatic fitting for coupling said first chamber to a source of air or vacuum;
a second pneumatic fitting for coupling said second chamber to a source of air or vacuum;
whereby said first piston and said second piston are independently movable and can press a wafer against the polishing pad with a force independent of the force applied to said retaining ring.

4 more elements

Dependencies are inferred from the claim text.

Pneumatic polishing head for CMP apparatus

Life of this patent

Pneumatic polishing head for CMP apparatus

Life of this patent

Abstract

Claims20