Beam angle control kit for angle sensitive implantation

Abstract

The unique dual axis tilt design of the gyro-super-disk (GSD) series end stations, as shown in figure 1, allow rapid adjustment of wafer tilt and twist angles and provide high throughput for multi-angle implantations. The treadmill of device scaling has been pushing for tighter process control in all sectors, including implant angle accuracy. Recently, there are rising demands for it to be tightened to < ±0.2°. The focus of this study is on high energy implantation with the beam angle normal (perpendicular) to the silicon wafer surface, corresponding to major axial crystal channeling. The obtained process results indicate high sensitivity in both device electrical performance and thermal-wave response to the angle variation even when it is within the original system specification of < ±0.5°. An implant beam angle control (BAC) kit was developed and tested to address the need of more accurate implant angle setup. The BAC kit includes a 2-dimentional beam angle measuring mask mounted on the implant disk, and an add-on software function to control the end station to the desired implant angle with improved accuracy, which is determined from the beam angle measuring mask. Once the beam angle measurement is performed after beam setup, but prior to wafer implant, the true implant angle will be obtained by moving the end-station disk to position. In this study, the BAC kit has been demonstrated with achieved angle accuracy of < ±0.15° after the angle variation from the beam setup is measured and compensated