Overview

The VIISta PLAD is a multi-chamber tool built on a platform common with Varian Semiconductor’s VIISta family of implanters, the only truly complete platform available that covers all implant segments. The VIISta PLAD implants the entire wafer simultaneously by positioning the wafer directly in a chamber containing plasma of the desired species. A pulsed DC voltage applied to the wafer draws ions from the plasma at a precisely controlled energy, resulting in extremely fast high-dose implants. Pulsing the bias voltage allows the system to automatically neutralize any charge buildup on the wafer surface between pulses and measure the ion dose per pulse using a Faraday for closed-loop in-situ dose control. With throughput up to six times greater than beamline or modified-source beamline technologies, the VIISta PLAD has become an attractive solution for critical low-energy, high-dose applications, such as DRAM (dynamic random access memory) polysilicon gate doping.