MORI (TM) high-density rf plasma source etching of polysilicon and metal films on wafers

Gregor A. Campbell; Alexis de Chambrier; Frank Mendoza; N. William Parker; David I. C. Pearson; Ken Tokunaga; Tsutomu Tsukada; Supika Mashiro; H. Nogami

doi:10.1117/12.142916

16 April 1993 MORI^TM high-density rf plasma source etching of polysilicon and metal films on wafers

Gregor A. Campbell, Alexis de Chambrier, Frank Mendoza, N. William Parker, David I. C. Pearson, Ken Tokunaga, Tsutomu Tsukada, Supika Mashiro, H. Nogami

Author Affiliations +

Proceedings Volume 1803, Advanced Techniques for Integrated Circuit Processing II; (1993) https://doi.org/10.1117/12.142916
Event: Microelectronic Processing '92, 1992, San Jose, CA, United States

Abstract

Etching of patterned doped poly-Si and of patterned W or Al metal wafers with high selectivity, high anisotropy, and high rate is achieved using the newly developed MORI rf plasma source. The source operates at low pressure (typically 1 - 3 mtorr) and at 13.56 MHz while achieving high efficiency through the generation of an m equals 0 Whistler wave often referred to as the m equals 0 helicon wave. The chlorine etch selectivity of poly-Si to SiO₂ can exceed 100, the selectivity of poly-Si to photoresist can exceed 10, and the poly-Si etch rate ranges from 2500 A/m to about 4000 A/m, depending upon wafer characteristics. The uniformity is less than 2% (1 sigma) and the chlorine ion saturation current exceeds 15 mA/cm² above the wafer location. Uniform, anisotropic etching of Al-1% Si-0.5% Cu using pure Cl₂ or Cl₂-(5-20%) BCl₃ at 1.5 - 3 mtorr achieves rates exceeding 6000 A/m with selectivity to photoresist (PR) of 9 and selectivity to oxide of 22 using a wafer rf bias power of 30 w at 13.56 MHz. Similarly excellent results are found in the etching of patterned W using SF₆ at 3 mtorr. Etch rates exceed 2500 A/m with selectivity to PR greater than 2 and selectivity to oxide greater than 10.

Citation Download Citation

Gregor A. Campbell, Alexis de Chambrier, Frank Mendoza, N. William Parker, David I. C. Pearson, Ken Tokunaga, Tsutomu Tsukada, Supika Mashiro, and H. Nogami "MORI^TM high-density rf plasma source etching of polysilicon and metal films on wafers", Proc. SPIE 1803, Advanced Techniques for Integrated Circuit Processing II, (16 April 1993); https://doi.org/10.1117/12.142916

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