Beam angle control on the VIISta 80 ion implanter

Abstract

Advanced integrated circuit design requires precise control of beam incidence angle. This requirement has led to the development of an automated angle control system on Varian Semiconductor's high current VIISta 80 ion implanter. In this paper we show beam incidence angle and angular spread measurements for 200 and 300 mm ion beams on the VIISta 80 ion implanter. Multiple beam measurements are sampled across the wafer plane for each beam setup. Beam angle computation results are compensated for prior to wafer implantation for optimal incident angle control. Beam, bare wafer and device performance data were used to confirm the accuracy of this measurement and control system. Excellent measurement accuracy and repeatability has been demonstrated. Data will be shown which includes arsenic, boron and phosphorus implants from both drift and decel operation. Benefits and process differences will be shown with active beam angle correction as compared to classical open loop methods. Mechanical tilt angle accuracy, repeatability and verification data will also be discussed.