Tungsten Film Chemical Mechanical Polishing Using MnO 2 Slurry

• Published in: Japanese Journal of Applied Physics Vol. 50; no. 7R; p. 76502
• Main Authors: Kishii, Sadahiro, Hatada, Akiyoshi, Arimoto, Yoshihiro, Kurokawa, Syuhei, Doi, Toshiro K.
• Format: Journal Article
• Language: English
• Published: 01.07.2011
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.50.076502

It has been demonstrated that MnO 2 abrasive can polish tungsten films without using an oxidizer solution. The polishing rate of MnO 2 slurry is 1.5 times higher than that of commercially available Al 2 O 3 slurry. A W plug is formed without etching holes (keyholes) during chemical mechanical polishing with MnO 2 abrasive slurry. With MnO 2 slurry, no key holes were formed even after overpolishing by an additional 0.6 µm. On the other hand, with conventional Al 2 O 3 slurry, keyholes were formed after overlpolishing by an additional 0.4 µm. The residual MnO 2 abrasive on the surface after chemical mechanical polishing was completely removed by the cleaning process because MnO 2 abrasive easily dissolves in a cleaning solution of HCl, H 2 O 2 , and H 2 O. These results indicate that, since MnO 2 is in itself a solid oxidizer, MnO 2 abrasive can polish W films without using an oxidizer solution and does not etch the seam.