Actual Rotation Angle Research Articles

Boron implant profile variation across a single wafer due to electrostatic scanning

The implanted impurity profile variation across a wafer due to an electrostatic scanning system has been studied for boron implants into (100) silicon wafers. The variation of the actual tilt and rotation angles across a wafer has been precisely determined for the implanter used in this study. The sensitivity of the impurity profiles to this angular variation has been studied through both a theoretical prediction based on an improved calculation of critical angles for channeling, and a qualitative analysis using the thermal wave measurement technique. A quantitative study of the profile variation across a wafer has also been performed using extensive secondary ion mass spectrometry (SIMS) profile measurements. For the energy range (15–80 keV) and angle range (0–10° tilt angle, 0–360° rotation angle) used in this study, we have identified the ranges of tilt and rotation angles that should be used for minimum channeling and minimum profile variation.