Ion implantation system and linear accelerator having novel accelerator stage configuration

A method of operating an ion implanter, comprising:

• generating an ion beam;
• bunching the ion beam, wherein the ion beam is transformed into a plurality of bunched ion packets;
• accelerating the bunched ion packets through a plurality of acceleration stages of a linear accelerator, wherein the accelerating comprises:
• in at least one stage of the plurality of acceleration stages, applying an RF signal to a drift tube assembly to accelerate the ion beam from an initial ion energy to a higher ion energy, without applying a quadrupole field to the ion beam, wherein the ion beam is focused by the drift tube assembly;
• and
• implanting the ion beam after passing through the linear accelerator into a substrate,
• wherein the plurality of acceleration stages individually comprise a drift tube assembly that includes a first grounded drift tube, an AC drift tube assembly, disposed downstream of the first grounded drift tube, a second AC drift tube, disposed downstream of the AC drift tube assembly, and a second grounded drift tube, disposed downstream of the second AC drift tube, and
• wherein at least one of the first grounded drift tube and the second grounded drift tube comprises a compact configuration, wherein the compact configuration comprises a drift tube length (L) and a drift tube diameter (D), wherein L/D is less than 2.

A linear accelerator, disposed within an ion implantation system, comprising:

• a plurality of acceleration stages, wherein at least one acceleration stage of the plurality of acceleration stages comprises:
• a drift tube assembly, arranged to receive and transport an ion beam as a bunched ion beam, the drift tube assembly comprising a triple gap configuration or a double gap configuration;
• and
• a resonator, electrically coupled to the drift tube assembly,
• wherein the drift tube assembly comprises a first grounded drift tube, an AC drift tube assembly, disposed downstream of the first grounded drift tube, and a second grounded drift tube, disposed downstream of the AC drift tube assembly,
• and wherein at least one of the first grounded drift tube and the second grounded drift tube comprises a compact configuration, wherein the compact configuration comprises a drift tube length (L) and a drift tube diameter (D), wherein L/D is less than 2.