A proposed magnetically enhanced reactive ion etcher for ULSI

An ultraclean (UC) magnetically enhanced reactive ion etcher (MERIE) is proposed to overcome the limitations of the present-state MERIE available commercially. The sensitivity of gas compositions, pumping speed, substrate temperature and magnetic field intensity are discussed as examples of hardware-related process limitations. Five major configuration changes are proposed in the system: (1) improved effective pumping speed; (2) supplementary magnets for uniform and stable plasma distribution; (3) dual RF excitation for independent control of ion energy and flux; (4) DC-biased shield electrode for minimum chamber material contamination; and (5) DC-biased substrate. A study with a dual RF excitation system found that DC-baising the Si substrate in low-energy SiO/sub 2/ etching process can significantly reduce the Si etching rate by impeding positive ions from reaching the substrate. In addition, SiO/sub 2/ to Si etching rate selectivity can be significantly improved during the overetch step in SiO/sub 2/ etching of high-aspect-ratio contact holes. >

[1]  J. Vossen,et al.  Thin Film Processes , 1979 .

[2]  C. Beneking,et al.  Power dissipation in capacitively coupled rf discharges , 1990 .

[3]  H. F. Winters,et al.  Plasma etching—A discussion of mechanisms , 1979 .

[4]  H. F. Winters,et al.  Ion‐surface interactions in plasma etching , 1977 .

[5]  K. Donohoe,et al.  Capacitive probes for rf process plasmas , 1989 .

[6]  T. Shibata,et al.  Formation of Copper Thin Films by a Low Kinetic Energy Particle Process , 1991 .

[7]  Tadahiro Ohmi,et al.  Independent control of ion density and ion bombardment energy in a dual RF excitation plasma , 1993 .

[8]  C. Steinbrüchel,et al.  Langmuir Probe Measurements on CHF 3 and CF 4 Plasmas: The Role of Ions in the Reactive Sputter Etching of SiO2 and Si , 1983 .

[9]  J. M. Smith.  Chemical Engineering Kinetics , 1980 .

[10]  C. Zarowin,et al.  Control of Plasma Etch Profiles with Plasma Sheath Electric Field and RF Power Density , 1982 .

[11]  C. J. Mogab,et al.  Plasma etching of Si and SiO2—The effect of oxygen additions to CF4 plasmas , 1978 .

[12]  D. Flamm,et al.  Reaction of fluorine atoms with SiO2 , 1979 .

[13]  Tadashi Shibata,et al.  A low damage, low contaminant plasma processing system utilizing energy clean technology , 1991 .

[14]  S. Brown,et al.  The admittance of high-frequency gas discharges , 1949 .

[15]  H. F. Winters.  The role of chemisorption in plasma etching , 1978 .

[16]  Kazunori Tsujimoto,et al.  Low‐temperature reactive ion etching and microwave plasma etching of silicon , 1988 .

[17]  Tadashi Shibata,et al.  Formation of High Quality Pure Aluminum Films by Low Kinetic Energy Particle Bombardment , 1990 .

[18]  E. Paradis.  The effect of magnetic fields on substrate temperature and film texture in an rf sputtering system , 1974 .

[19]  G. Smolinsky,et al.  The effect of added hydrogen on the rf discharge chemistry of CF4, CF3H, and C2F6 , 1979 .

[20]  R. D'agostino,et al.  Mechanisms of etching and polymerization in radiofrequency discharges of CF4–H2, CF4–C2F4, C2F6–H2, C3F8–H2 , 1983 .

[21]  Tadahiro Ohmi,et al.  Formation of device‐grade epitaxial silicon films at extremely low temperatures by low‐energy bias sputtering , 1989 .