FRAUNHOFER IISB STRUCTURE SIMULATION Eberhard Bär eberhard.baer@iisb.fraunhofer.de Page 1
FRAUNHOFER IISB STRUCTURE SIMULATION Overview SiO 2 etching in a C 2 F 6 plasma Ga ion beam sputter etching Ionized metal plasma (IMP) deposition Oxide deposition processes Superconformal copper deposition Coupled simulation of deposition and etching Stressed AlSiCu interconnect line Hierarchical modeling of coils consisting of litz wires Potential distribution in copper-ceramics substrate Coupling of topography simulation and electrical extraction Page 2
Structure Simulation Overview Simulation of various structures Microelectronic devices or interconnects Semiconductor manufacturing equipment Macroscopic structures, e.g., for power electronic applications Software integration E.g., TCAD suites, electrical, thermal and mechanical modeling with FEM software such as ANSYS Modeling of structure evolution for microelectronic applications Etching, deposition, CMP Modeling of structures under operation Electrical, thermal, mechanical behavior Reliability of passive components, e.g. due to electromigration Page 3
Simulation of SiO 2 Etching in C 2 F 6 Plasma Influence of Equipment Parameters on Feature Profile Neutral flux j neut,0 at surface Ion flux j ion,0 at surface Neutral flux j neut,0 at surface Ion flux 5*j ion,0 at surface Page 4
Simulation of Ga Ion Beam Sputter Etching z (microns) Comparison between simulation and experiment (grey region: data obtained from scanning electron microscopy (SEM) image) Monte Carlo Simulation x (microns) Page 5
Simulation of Ionized Metal Plasma (IMP) Deposition Influence of Bias Bias = 20 V => resputtering 0 Bias = 100 V => resputtering 0.4 Sticking coefficient of metal atoms and metal ions = 1 Isotropic angular distribution of metal atoms Bias = 20 V Bias = 100 V Page 6
Simulation of Low-Temperature Oxide Deposition for the Formation of Air Gap Dielectrics Simulation for precursor sticking coefficient = 0.4 Data: EU project PULLNANO Page 7
Simulation of Plasma-Enhanced Chemical Vapor Deposition (PECVD) of Oxide Model: Rate contributions are due to Neutrals (radicals): isotropic angular distribution Ions: Gaussian distribution Local rate R PECVD ~ ( s c F neutral + F ion ), with F: local particle flux, s c : neutral sticking coefficient Model parameters: r = R neutral / ( R neutral + R ion ) in 1D regions, sticking coefficient of neutrals s c, of Gaussian distribution for ions Implementation F neutral from model which determines adsorption and re-emission of reactive molecules or radicals, F ion from flux integration of the ions Page 8
PECVD of SiO 2 with TEOS Chemistry Oxygen Plasma Simulation with Quantemol Q-VT Neutrals (O) Ions (O 2 +) Example for concentration of neutrals (O) and ions (dominant ion species is O 2 +) in a CCP reactor Page 9
PECVD of SiO 2 with TEOS Chemistry Feature-Scale Model with Ion Support for Deposition SiO 2 layer deposited in hole position at 0.0 cm position at 10.0 cm Page 10
Simulation of Superconformal Copper Deposition Simulation of deposition into trench and via under identical conditions (agreement with experimental data for superconformal CVD) Trench Via Page 11
Simulation of Plasma-Enhanced CVD (PECVD) Simulation for two trenches with different aspect ratios Model parameters: r = R neutral / ( R neutral + R ion ) = 1 s c = 0.18 Page 12
Influence of Ion Energy on Profile after Back Etching Simulated profiles after sputter etching for different energies of the Ar ions (upper curve: 250 ev, middle curve: 200 ev, lower curve: 180 ev) Page 13
Comparison of Simulation and Experiment Data: FhG IMS, Duisburg Simulation (for Ar ion energy = 250 ev) of sputter etching in comparison to the experimental data, good agreement for both trenches is obtained Page 14
Modeling of Stressed AlSiCu Interconnect Line Vacancy concentration in interconnect line as criterion for time-tofailure to allow comparison to experimental data w L Example for simulated vacancy distribution c v along metal line under current and thermal stress Page 15
Hierarchical Modeling of Coils Consisting of Litz Wires 30A Page 16
Potential Distribution in Copper-Ceramics Substrate Copper at 10 kv Gel Conducting interlayer Ceramic Layer 1 Ceramic Layer 2 Copper at 0kV Page 17
Coupling of Process Simulation and Electrical Characterization Simulated interconnect geometry Current density distribution simulated with STAP, TU Vienna Page 18