Chinese 中文


The term "pellicle" is used to mean "film," "thin film," or "membrane." Beginning in the 1960s, thin film stretched on a metal frame, also known as a "pellicle," was used as a beam splitter for optical instruments. It has been used in a number of instruments to split a beam of light without causing an optical path shift due to its small film thickness. In 1978, Shea et. al. at IBM patented a process to use the "pellicle" as a dust cover to protect a photomask or reticle(hence will all be called "photomask" in the rest of this chapter) In this chapter, the word "pellicle" will be used only to mean a "thin film dust cover to protect a photomask".