Mitigating Cleanroom Noise Can Improve Tool Performance

摘要

Most high-resolution semi-conductor inspection tools are extremely sensi-tive to the cleanroom en-vironment.. Even a minute disturbance can have a significant impact on image quality for a high-magnification tool such as a scanning electron microscope (SEM). These disturbances disrupt the path between the imaging optics and the wafer in a random and/or oscillatory fashion. Common cleanroom sources that can affect the tool performance include floor vibrations, acoustic noise and electro-magnetic interference (EMI). Figure 1 illustrates the effect of these noise sources on image quality.