Speedfam-ipec Corporation

Integrated Process Equipment Corporation

Fred E Mitchel

John Andrew Adams

Chris E Barns

Thomas Frederick Bibby, Jr

Ajoy Zutshi

Dennis Schey

Karey Holland

Lin Yang

C Jerry Yang

Kenneth D Lefton

Yehiel Gotkis

Malek Charif

Fen Dai

A multi-step CMP system is used to polish a wafer to form metal interconnects in a dielectric layer upon which barrier and metal layers have been formed. A first polish removes an upper portion of the metal layer using a first slurry and a first set of polishing parameters, leaving residual metal within the dielectric layer to serve as the metal interconnects. A second polish of the wafer on the same platen and polishing pad removes portions of the barrier layer using a second slurry under a second set of polishing parameters. The second polish clears the barrier layer from the upper surface of the dielectric layer, thereby forming the metal interconnect. To reduce dishing and dielectric erosion, the second slurry is selected so that the barrier layer is removed at a faster rate than the residual metal within the dielectric layer. A cleaning step may be optionally performed between the first and second polishes. Further, the first polish may include a soft landing step to further reduce dishing and dielectric erosion. Alternatively, the first polish may be used to remove portions of the metal and barrier layers, leaving residual metal in the dielectric layer to serve as the metal interconnect. A second polish using a dielectric slurry is then performed to reduce microscratches.

Multi-step chemical mechanical polishing

A carrier head for a semiconductor wafer polishing apparatus includes a rigid plate which has a major surface with a plurality of open fluid channels. A flexible wafer carrier membrane has a perforated wafer contact section for contacting the semiconductor wafer, and a bellows extending around the wafer contact section. A retaining member is secured to the rigid plate with a flange on the bellows sandwiched between the plate's major surface and the retaining ring, thereby defining a cavity between the wafer carrier membrane and the rigid plate. A fluid conduit is coupled to the rigid plate allowing a source of vacuum and a source of pressurized fluid alternately to be connected to the cavity. An additional wafer carrier membrane is internally located with respect to the cavity formed by the wafer carrier membrane, and forms another cavity with respect to the rigid plate. Another fluid conduit is connected to the internal wafer carrier membrane's cavity, which is selectively pressurized to make the internal wafer carrier membrane contact the wafer contact section.

Semiconductor wafer polishing apparatus with a variable polishing force

A carrier head for a semiconductor wafer polishing apparatus includes a rigid plate which has a major surface with a plurality of open fluid channels. A flexible wafer carrier membrane has a perforated wafer contact section for contacting the semiconductor wafer, and a bellows extending around the wafer contact section. A retaining ring is secured to the rigid plate with a flange on the bellows sandwiched between the plate's major surface and the retaining ring, thereby defining a cavity between the wafer carrier membrane and the rigid plate. A fluid conduit is coupled to the rigid plate allowing a source of a vacuum and a source of pressurized fluid alternately to be connected to the cavity.

Semiconductor wafer polishing apparatus with a flexible carrier plate

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Phoenix, AZ, United States of America

Fred E Mitchel