ABSTRACT
This chapter discusses the nomenclature and methods used to transfer a pattern from a mask to a layer to be etched by plasma-related etching processes. Plasma etching is a technology essential to microelectronic circuit fabrication. A negative feature of plasma etching is the requirement that the etching process be conducted in a vacuum system. The endpoint of an etching process occurs when the trench reaches the intended depth in the etched layer. This usually occurs when the trench arrives at the substrate and completely transfers the pattern on the mask to the etched layer. To prevent excessive over-etching, endpoint detection is used to determine when an etching operation is complete. Usually, when the etching process reaches the substrate, the flux of etching reaction products suddenly decrease. The ideal etching agent would be selective and etch a layer vertically and rapidly, while leaving the mask and the substrate unaffected. This would produce the ideal selective etch.
