Back pressure control system for CMP and wafer polishing
AssigneeStrasbaugh
InventorAlan Strasbaugh
Life of this patent
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Abstract
A wafer carrier with a back pressure applicator system adapted to provide high resolution back pressure control. A plurality of millimeter scale distensible elements are disposed between the wafer carrier pressure plate and a process wafer, and selectively distended to provide excess backpressure to select small areas of a wafer known to exhibit resistance to removal vis-á-vis the surrounding wafer surface. Distensible elements may be in the form of expandable pneumatic chambers or electro-mechanical elements such as solenoids, shape memory elements, electrostatic plates, etc.
Claims5
A wafer carrier for use in wafer polishing, said wafer carrier comprising a carrier housing, a pressure plate and a retaining ring surrounding the pressure plate and extending below the pressure plate to form a cylindrical recess sized to receive the wafer, said wafer carrier further comprising:
- a plurality of downwardly distensible elements;
- wherein the downwardly distensible elements comprise expandable chambers;
- and
- wherein the distensible elements are disposed within a removable disk disposed below the pressure plate and within the bounds of the cylindrical recess.
A wafer carrier for use in wafer polishing, said wafer carrier comprising a carrier housing, a pressure plate and a retaining ring surrounding the pressure plate and extending below the pressure plate to form a cylindrical recess sized to receive the wafer, said wafer carrier further comprising:
- a plurality of downwardly distensible elements disposed on or below the bottom surface of the pressure plate wherein the downwardly distensible elements comprise expandable chambers;
- a manifold within the pressure plate in fluid communication with a pressurized fluid source;
- a plurality of fluid pathways communicating from the manifold to the expandable chambers;
- and
- a plurality of valves disposed in the fluid pathways, said valves being operable to maintain pressure in the expandable chambers.
Dependencies are inferred from the claim text.