An isothermal processing system using a 2hyphen;kW electron beam is described. Processing of areas up to 4times;4 in. is achieved by rapidly scanning the beam in the multiple scan mode. An analysis of this method and some typical heating cycles for silicon wafers are presented. There is good agreement between theoretically predicted and experimentally measured temperatures. Additionally, closedhyphen;loop operation is demonstrated where an optical pyrometer is used to control the electron beam current. This machine can either process whole wafers, or can sequentially treat a large number of small chips. This enables, for example, the rapid assessment of the annealing behavior of a particular implant by processing chips, cut from the same wafer, under varying conditions. Heating cycles of a fraction of a second to tens of seconds or more, which are not possible with furnaces, at temperatures up to 1000deg;C or greater have found many applications in semiconductor processing. Two important uses are described in this paper illustrating the potential of the technique. One is the annealing of an arsenic implant in silicon with negligible diffusion and the other is the controlled drive in of arsenic.
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