Wafer cooling for a high current serial ion implantation system

This paper investigates performance of a gas-cooled, low temperature electrostatic chuck and the effects of gas injection radius change on the wafer cooling efficiency. Wafer temperature measurements were taken for two new electro-static chuck designs at different gas cooling pressures during high current ion implantation. Typical input beam power density was 1.3 W/cm/sup 2/. An improvement in cooling performance was achieved with the platen having the largest gas injection radius. Wafer radial temperature profile was modeled for both 200 and 300 mm wafers. The possibility of improved performance is discussed for alternative cooling gases such as CH/sub 4/ and NH/sub 3/.