Usage in Semiconductor Fabrication
Before about 1990 CMP was looked on as too "dirty" to be included in high-precision fabrication processes, since abrasion tends to create particles and the abrasives themselves are not without impurities. Since that time, the integrated circuit industry has moved from aluminium to copper conductors. This required the development of an additive patterning process, which relies on the unique abilities of CMP to remove material in a planar and uniform fashion and to stop repeatably at the interface between copper and oxide insulating layers (see Copper-based chips for details). Adoption of this process has made CMP processing much more widespread. In addition to aluminum and copper, CMP processes have been developed for polishing tungsten, silicon dioxide, and (recently) carbon nanotubes.
Read more about this topic: Chemical-mechanical Planarization
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