In a broad sense, metal polishing is an extremely ancient technology that has long been used to make beautiful objets d’art as well as utilitarian objects. However, within the context of modern microelectronics it is a much more narrowly defined technology that is invariably used to fabricate “damascene” structures. The origin of this terminology is obscure, however for integrated circuit fabrication damascene means microscopic, inlaid metal features that serve as “wiring” to connect individual electronic components, e.g., transistors, previously formed in an underlying semiconductor substrate (usually a single crystal silicon wafer). Of course, the overall objective is fabrication of functional devices such as microprocessors or memories. Naturally, to serve this purpose metal wiring must be inlaid in some insulating material (typically a silica based glass) with appropriate provision made for interconnections between wires and the substrate and between the wires themselves. Indeed, in the case of complex devices such as microprocessors or sophisticated logic circuits, several layers of both horizontally and vertically interconnected damascene structures must be fabricated to form a “multilayer interconnect” in order to accommodate required connections between tens of millions of components.
Post time: Apr-14-2017