A molecular dynamics investigation of fluorocarbon based layer-by-layer etching of silicon and SiO2

A molecular dynamics model is used to understand the layer-by-layer etching of Si and SiO2 using fluorocarbon and Ar+ ions. In these two-step etch processes, a nanometer-scale fluorocarbon passivation layer is grown on the material’s surface using low energy CFx+ ions or radicals. The top layers of the material are then reactive ion etched by Ar+ ions utilizing the fluorocarbon already present on the material surface. By repeating these two steps, Si or SiO2 can be etched with nanometer-scale precision and the etch rate is considerably faster than what traditional atomic layer etching techniques provide. The modeling results show that fluorocarbon passivation films can be grown in a self-limiting manner on both Si and SiO2 using low energy CF2+ and CF3+ ions. The fluorocarbon passivation layer is a few angstroms thick, and its thickness increases with the fluorocarbon ion’s energy. Increasing the ion energy, however, amorphizes the top atomic layers of the material. In addition, the fluorocarbon film beco...

[1]  Masaru Hori,et al.  Fluorocarbon radicals and surface reactions in fluorocarbon high density etching plasma. II. H2 addition to electron cyclotron resonance plasma employing CHF3 , 1996 .

[2]  Molecular dynamics simulations of Si etching with energetic F+: Sensitivity of results to the interatomic potential , 2000 .

[3]  Shahid Rauf,et al.  Molecular-dynamics model of energetic fluorocarbon-ion bombardment on SiO2 I. Basic model and CF2+-ion etch characterization , 2005 .

[4]  T. Matsuura,et al.  Atomic-layer surface reaction of chlorine on Si and Ge assisted by an ultraclean ECR plasma , 1998 .

[5]  D. Lee,et al.  Atomic Layer Etching of Si(100) and Si(111) Using Cl2 and Ar Neutral Beam , 2005 .

[6]  Y. Sawada,et al.  Self‐limited layer‐by‐layer etching of Si by alternated chlorine adsorption and Ar+ ion irradiation , 1993 .

[7]  S. Rossnagel,et al.  Plasma-enhanced atomic layer deposition of Ta and Ti for interconnect diffusion barriers , 2000 .

[8]  D. Graves,et al.  Atomistic simulation of fluorocarbon deposition on Si by continuous bombardment with energetic CF+ and CF2+ , 2001 .

[9]  M. Sekine,et al.  Observation of surface reaction layers formed in highly selective SiO2 etching , 2001 .

[10]  C. Aldao,et al.  Halogen etching of Si via atomic-scale processes , 2001 .

[11]  Miyako Matsui,et al.  Relationship of etch reaction and reactive species flux in C4F8/Ar/O2 plasma for SiO2 selective etching over Si and Si3N4 , 2001 .

[12]  S. Shingubara,et al.  Digital etching study and fabrication of fine Si lines and dots , 1993 .

[13]  T. Matsuura,et al.  Atomic-order layer-by-layer role-share etching of silicon nitride using an electron cyclotron resonance plasma , 1999 .

[14]  M. Hori,et al.  Surface reaction of CF2 radicals for fluorocarbon film formation in SiO2/Si selective etching process , 1998 .

[15]  N. R. Rueger,et al.  Selective etching of SiO2 over polycrystalline silicon using CHF3 in an inductively coupled plasma reactor , 1999 .

[16]  Weaver,et al.  Determination of dynamic parameters controlling atomic scale etching of Si(100)-(2 x 1) by chlorine. , 1995, Physical Review Letters.

[17]  C. Hedlund,et al.  Selective SiO2-to-Si3N4 etching in inductively coupled fluorocarbon plasmas: Angular dependence of SiO2 and Si3N4 etching rates , 1998 .

[18]  T. Matsuura,et al.  Atomic-layer etching of Ge using an ultraclean ECR plasma , 1997 .

[19]  Je-Hun Lee,et al.  Thermal stability and structural characteristics of HfO2 films on Si (100) grown by atomic-layer deposition , 2002 .

[20]  Y. Aoyagi,et al.  Control of the etching reaction of digital etching using tunable UV laser irradation , 1994 .

[21]  Hyungjun Kim,et al.  Atomic layer deposition of metal and nitride thin films: Current research efforts and applications for semiconductor device processing , 2003 .

[22]  Satoshi Hamaguchi,et al.  Molecular dynamics simulation of silicon and silicon dioxide etching by energetic halogen beams , 2001 .

[23]  D. J. Economou,et al.  Realization of atomic layer etching of silicon , 1996 .

[24]  W. Tsang,et al.  Monolayer chemical beam etching: Reverse molecular beam epitaxy , 1993 .

[25]  H. Berendsen,et al.  Molecular dynamics with coupling to an external bath , 1984 .

[26]  D. Graves,et al.  Molecular dynamics simulations of Si etching by energetic CF3 , 1999 .

[27]  D. J. Economou,et al.  Molecular dynamics simulation of atomic layer etching of silicon , 1995 .

[28]  D. Graves,et al.  On the active surface layer in CF3+ etching of Si: Atomistic simulation and a simple mass balance model , 2000 .

[29]  S. Rauf,et al.  Molecular-dynamics model of energetic fluorocarbon-ion bombardment on SiO2. II. CFx+ (x=1, 2, 3) ion etch characterization , 2005 .

[30]  M. Barela,et al.  Fluorocarbon-based plasma etching of SiO2: Comparison of C4F6/Ar and C4F8/Ar discharges , 2002 .

[31]  Seiichi Miyazaki,et al.  Digital chemical vapor deposition and etching technologies for semiconductor processing , 1990 .

[32]  Marc Schaepkens,et al.  Study of the SiO2-to-Si3N4 etch selectivity mechanism in inductively coupled fluorocarbon plasmas and a comparison with the SiO2-to-Si , 1998 .

[33]  J. Banavar,et al.  Computer Simulation of Liquids , 1988 .

[34]  H. Sakaue,et al.  Atomic Layer Controlled Digital Etching of Silicon , 1990 .

[35]  K. Ikeda,et al.  Atomic layer etching of germanium , 1997 .

[36]  Atomic layer etching and sidewall roughness measurement using the scanning tunneling microscope , 1992 .

[37]  Weaver,et al.  Layer-by-layer etching of Si(100)-2 x 1 with Br2: A scanning-tunneling-microscopy study. , 1993, Physical review. B, Condensed matter.