Ion implanter with wafer angle and faraday alignment checking

摘要

A beam/wafer alignment arrangement has a laser and sensor mounted on the scanning magnet. Direct alignment of the wafer relative to the scanning magnet is determined by reflecting the beam in a specular surface on the wafer holder back to the sensor. Correct alignment of the wafer translation direction is also confirmed from any movement of the reflected light spot on the sensor as the wafer holder is translated up and down. A further sensor is mounted on the beam stop to monitor any misalignment of the process chamber to the collimator magnet, and for checking the location of the travelling Faraday.