Image improvement with modified scanning waves and noise reduction in a scanning electron microscope

In order to acquire a high-resolution image in a scanning electron microscope (SEM), a well-modulated current profile on the deflection coil must be generated by a scan waveform, and a properly selected scan waveform can eliminate the distortion of the image. In this work, various adjustments to the scan waveform, including the frequency, slope, and flatness, were analyzed. A new scan waveform using sinusoidally varying voltages was found to reduce distortion, particularly at the outer range image. The SEM image was also improved by reducing noise from the driver circuit and separating electrical grounding of the scanning coils.