AVS 50th International Symposium
    Plasma Science and Technology Wednesday Sessions
       Session PS2-WeM

Paper PS2-WeM6
High Rate Etching of SiC in Ultrahigh Density Plasmas Excited by Electron Cyclotron Resonance

Wednesday, November 5, 2003, 10:00 am, Room 315

Session: Etching Difficult Materials
Presenter: K. Nakamura, Mitsubishi Electric Corporation, Japan
Authors: K. Nakamura, Mitsubishi Electric Corporation, Japan
M. Tuda, Mitsubishi Electric Corporation, Japan
M. Taki, Mitsubishi Electric Corporation, Japan
K. Shintani, Mitsubishi Electric Corporation, Japan
H. Sumitani, Mitsubishi Electric Corporation, Japan
Correspondent: Click to Email
Silicone carbide (SiC) is a promising substrate material for advanced high power devices, high frequency devices, and microelectoromechanical systems, because of good electrical, mechanical, and chemical properties. Fabrication for these devices, deep etching of SiC with a high rate and high selectivity to mask material is required. Etching of SiC is known to be difficult since its bonding energy is relatively larger than those for conventional Si and GaAs. Recently, fast SiC etching with an etch rate of ~1 µm/min has been reported,@footnote 1,2@ where high density ICP and Helicon Plasma sources were used. However, a much higher etch rate is needed for the bulk micromachining (typically, etched depth >100 µm) of SiC substrates. In this study, we have developed fast SiC etching processes using a ultrahigh density plasma source excited by electron cyclotron resonance (ECR); the plasma density measured for Ar was 10@super 12@-10@super 13@ cm@super -3@, and the ion current density onto a substrate stage was more than 100 mA/cm@super 2@. Etching of 4H-SiC was performed in SF@sub 6@/O@sub 2@ plasmas by varying gas pressure, flow rate, O@sub 2@ concentration, microwave power, and rf-bias power. With increasing microwave and rf-bias powers, the SiC etch rate increased up to ~8 µm/min. A high etch rate (>5 µm/min) and selectivity (>50 to Ni) was simultaneously obtained under optimized conditions. These results show that ultrahigh density ECR plasmas are desirable for SiC bulk micromachining. @FootnoteText@ @footnote 1@ F. A. Khan and I. Adesida, Appl. Phys. Lett. vol.75 2268 (1999)@footnote 2@ P. Chabert, N. Proust, J. Perrin, and R. W. Boswell, Appl. Phys. Lett. vol.76 2310(2000) .