For circuit integration※of semiconductor devices, a finer and more multi-stratified wire circuit on the semiconductor wafer is indispensable. This is supported by a CMP system that planarizes fine irregularities on the surface of the semiconductor wafer.
The semiconductor device is realized by forming thin film of insulating material and conductive material on the surface of wafer with the use of a dedicated device and processing it into a fine circuit. In this process, however, the surface of the circuit becomes uneven. The CMP system turns it into a flat surface with roughness in the range of 10 to 20nm, which is equivalent to irregularity of 0.5mm on the inner side of the Yamanote rail line (with average diameter of 10km). With such high-accuracy planarization, we can laminate more than ten layers of fine circuits and thereby realize the high-level circuit integration of semiconductor devices.
The CMP system polishes a rotating wafer by pressing it on a rotating table attached with resin sheet, while pouring polishing liquid that contains fine abrasive grains and chemical solution. Ebara is a pioneer that has developed the Dry-in/Dry-out system for performing polishing, cleaning and drying inside CMP system in order to adapt polished wafers to the clean manufacturing environment of semiconductors and thereby enable installation of CMP system in clean rooms.
※Circuit integration: Circuit integration refers to forming many transistors and memory elements within a semiconductor device of limited area, thereby enabling higher performance to be combined with more compact size.