Chemical mechanical polish

From ArticleWorld

The process of chemical-mechanical planarization is a technique used in semiconductor fabrication for the purpose of planarizing the top surface of a wafer. This technique combines chemical action with mechanical abrasion to achieve selective removal of material. The final polished wafer or other substrate achieves the greatest degree of planarization of any known method in existence.

How the process is carried out

The technique involves an abrasive along with slurry which is used in combination with a polishing surface. The surface and the wafer are kept in contact with each other at high pressure. The polishing head used in this process is rotated at required speeds, to achieve the desired degree of planarization. Any amount of microscopic ridges and furrows can be got rid of by this method.

The chemicals which are present in the slurry chemically react with the material that is to be removed. The process of such a weakening action is boosted by the use of abrasives. Chemical-mechanical planarization has increased in popularity due to recent improvements.

Important factors involved

The proper implementation of chemical-mechanical planarization requires the following factors to be taken care of:

  1. Wafer pressure involved.
  2. Wafer rotation speed.
  3. Temperature involved in the process.
  4. Type of slurry used and the rate of its dispense.
  5. Type of the polishing pad used and its conditioning.