Plasma particulate contamination control. II. Self‐cleaning tool design

Macroscopic particles are often observed in etching, sputtering, and deposition plasmas, in laboratory and manufacturing tools, in concentrations far exceeding ambient cleanroom conditions and acceptable process specifications. Controlling particle contamination is an important goal in modern fabrication lines. Controlling plasma‐generated particulates is especially important as these tools and processes are a major source of wafer contamination. Plasma particles acquire negative charge by electron attachment and are influenced by electric fields and plasma inhomogeneities. Improper tool design exacerbates tool contamination problems by trapping particles near wafers or other sensitive surfaces. Conversely, proper tool and electrode design can provide greatly improved contamination results. The concept of a self‐cleaning plasma tool is presented for the first time, along with evidence of the effectiveness and usefulness of this approach in laboratory and manufacturing studies. The method does not reduce t...