Production proven electrostatic platen for medium current implantation

Electrostatic wafer platens (ESPs) for ion implant systems offer enormous benefits in manufacturing productivity. This paper describes and compares the performance of the standard clamp in current use in more than 50 user sites with a new cooled platen design. As would be expected the ESP platens do not affect dosing, charging, or front side particulates. Device damage from the ESP is not an issue because of the safe AC operating mode. Cooling performance of 1 watt/cm/sup 2/ for 200 mm wafers using nitrogen as the cooling gas has been obtained. Tests indicate that backside particles are dependent on the surface smoothness of the platen and the smoothness of the back side of the wafer being clamped.