Absolute Dose Performance of the SWIFT Single Wafer Ion implanter

The characteristics of a new high performance implanter ("SWIFT") manufactured by Applied Materials include high accuracy implantation angle control, minimal energy spread [and uniformity and repeatability of dose [<0.5%] at various beam incident angles up to 60 degrees from normal. The latter is achieved using beam current monitoring equipment designed to measure absolute dose. It should be mentioned that although repeatability is much more important than absolute accuracy in implanter dosimetry, absolute accuracy is very convenient, making cross-machine comparisons, the establishment of new processes and day to day validation of different processes much easier. Four silicon wafers implanted by SWIFT at about 5*1015 As/cm2 were analysed by Rutherford backscattering spectrometry in order to characterise the absolute dosimetry of this implanter with an accuracy of 1.6% traceable to the international standard of weight in Paris. Repeatability and internal consistency of the RBS could be demonstrated at the 1% level consistent with the expected statistical and other errors. We could also find no significant error in the implanter dosimetry