Matching the injected ion beam into an rf Linac for a high-energy, high-current ion implanter

Over the last several years, high-energy (in the MeV range) ion implantation has become an integral part of mainstream semiconductor device manufacturing. The rapid growth in the use of the high-energy ion implanters has been driven by device engineering process requirements. At Eaton, we have developed an rf Linac based high-energy implanter, NV-GSD/VHE, capable of delivering 1.7 MeV B + beam in excess of 1 mA. However, as high-dose buried layers and 300 mm substrates emerge for mainstream integrated circuit processing, a need for a significantly higher B + beams up to 2 MeV is on the horizon. To maximize the beam transmission, optimizing the match between the injected ion beam and the Linac acceptance is essential. A pepper-pot emittance measurement apparatus is used to measure the beam emittance down stream of the ion source extraction optics. The ion source beam emittance requirement, its measured and theoretical values for our ion source will be discussed.