Beam tuning with continuously variable aperture

In order to obtain more productivity on the high energy ion implanter, chained implantations are used. The chained implantations man a combination of recipes with the same species but different energies and doses in one batch. Wafers are implanted with a series of these recipes in the same batch. In this case it is very important and effective to reduce beam tuning time. On the NV-GSD-HE and NV-GSD-HE3, the ion energy can be quickly changed only by loading the different linac parameters, but the beam current usually can not be tuned quickly or easily. The Continuously Variable Aperture (CVA) has been developed and mounted between the injector and the linac in order to change the beam current quickly only by adjusting the width of aperture and partially cutting the injection beam to the linac mechanically. With the CVA, ail the recipes in the chained implantations must have the same Injector beam current. For such chained recipes, the automatic beam setup program can skip the injector tuning and tunes only the width of the CVA to get the ordered current. As a result of the evaluation test, the CVA tuning takes about 30 seconds in average and a total recipe change time is less than one minute. The CVA shows much improvement on the productivity on the retrograde well formation process.