Julian A. Montoya and Vincent Esqueda, Intel Corporation
As semiconductor devices shrink in size to accommodate Moore’s Law, the need for high-resolution beam-based metrology and beam-based writing equipment increases, and the dependence of such equipment for process development and process validation becomes ever more critical. For the purposes of this discussion, beam-based metrology and writing equipment will be defined as equipment that utilizes an electron beam to perform its intended function. Examples include but are not limited to: scanning electron microscopes (SEMs), transmission electron microscopes (TEMs), and photomask writing equipment. Research has shown that these classes of equipment are highly sensitive to magnetic-field interference where the interaction of magnetic field and electron beam leads to less than optimum tool performance. A basic understanding of the problem along with early planning and operational diligence can help prevent magnetic-field interference from occurring. The remainder of this discussion will revolve around introducing the topic of magnetic-field interference of beam-based equipment, the challenges posed by this interference mechanism, the typical causes and sources of interference, considerations for measuring the interference, and the mitigation options available to address the interference concern.