What Is a Chemical Mechanical Polishing (CMP) Machine?
CMP machine is used to polish silicon wafers. Semiconductors are made on a tiny scale, requiring uniform, high-precision polishing. In addition, they have many layers of different hardness, each of which must be polished using the appropriate pressure, abrasives, and chemicals. During polishing, the surfaces and irregularities are chemically reacted and mechanically removed with sandpaper or other tools according to the composition of each semiconductor layer.
Uses of CMP Machines
CMP machines are mainly used in the semiconductor manufacturing process. CMP is used in the semiconductor process to flatten the uneven surface after etching, oxide film formation, ion diffusion, etc. CMP allows for precise flattening and facilitates further layering on the flattened surface. When selecting a CMP system, it is necessary to consider the planarization accuracy, the chemicals and fluids used, and the processing speed of the silicon wafers.
Principles of CMP Machines
This section describes the principle of operation of CMP machines, which are generally large, to process a large number of silicon wafers at a time at high speed. The components are a rotating stage, a polishing section with nozzles for applying chemicals and chemicals, sandpaper, etc. In addition, a robot for transporting silicon wafers, a cleaning section after polishing, and a detection section above are also included.
The essential operation is to spray chemicals and chemical agents onto silicon wafers through nozzles, press sandpaper, etc., onto the wafers, and polish them by rotating the stage at high speed. The targets of chemical polishing are oxide film, tungsten wiring, and copper wiring. In the case of oxide film, the film is dissolved in an alkaline solution and polished with silicon oxide of the same composition. For tungsten wiring, the surface portion of tungsten is oxidized, and the surface is polished with silicon oxide. In the case of copper wiring, the copper is oxidized, then complexed and polished with silicon oxide, etc.