8250 electrostatic clamp performance

The need for higher yields and reduced contamination have been driving factors for developing and using electrostatic wafer clamps. Electrostatic Clamps (ESC) do not make contact with the device side of the wafer which reduces particle adders. This feature increases the real estate available for devices on the wafer, increasing yield. Decreased exposure of the clamp mechanism to the ion beam also reduces contamination through sputtering. Wafer cooling using chilled fluid circulation within the electrostatic clamp yields heat transfer results of greater than 0.25 W/cm/sup 2/ (100/spl deg/C rise) without the aid of cooling gasses. Clamp alignment is made easier and quicker with the electrostatic clamp. Emphasis is placed on wafer cooling, surface particle and metal contamination data.