Synopsys Topography Simulations
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Synopsys Topography Simulations The Second Quantemol Workshop Synopsys London, November 7, 2012 ©Synopsys 2012 1 Outline Sentaurus Topography 3D introduction SPTOPO3D project setup Input file for the built in Ionmill model Input file for the RFM sputtering model ©Synopsys 2012 2 What is TCAD ? Process Simulation Device Simulation Current in Drift-Diffusion Model PDE for Pair Diffusion Potential distribution in flash memory LDMOS: doping, mesh 1D doping profile simulation Inductance Simulation PVD (Physical Vapor Deposition) Emulation of 4 CIS cells Mechanical stress in intermetal dielectric ©Synopsys 2012 3 Snapback of a UMOS AlGaAs VCSEL Full Chip H-Bridge EM Wave Sentaurus TCAD Product Line Framework Process Simulation Structure Editing Device and Interconnect Simulation ©Synopsys 2012 4 Sentaurus Process Sentaurus Topography Sentaurus Workbench Sentaurus Structure Editor Sentaurus Device Raphael Sentaurus Interconnect Sentaurus Visual Sentaurus PCM Studio Sentaurus Topography Main Features • 2D and 3D feature-scale profile simulator, levelset-based • Built-in empirical models: – Deposition: LPCVD, PVD, HDP, Electroplating – Etching: RIE, HDP, Ion-enhanced • Including physical effects of sputtering, reemission, re-deposition, and ion reflection • Input particle flux defined by IAD • Surface reaction model (2D) • Programmable Model Interface (PMI, C++) • User Rate Formulation Model (RFM) • Integrated with Sentaurus Process and Sentaurus Interconnect ©Synopsys 2012 5 Sentaurus Topography 3D • Sentaurus Topography 3D is a three-dimensional simulator for evaluating and optimizing critical topography-processing steps such as etching and deposition • It simulates deposition and etching processes by using the level-set method to evaluate the boundary evolution during the process • Models categories: – Built-in models – User-defined models within Rate Formula Module (RFM) – User-defined models within a Physical Model Interface (PMI) • Support of different reaction species, different fluxes, re-deposition, … ©Synopsys 2012 6 Sentaurus Topography 3D Capabilities • Etching (10 models) – • Deposition (7 models) – • • • HDP, HDP2, LPCVD, PECVD, PVD, Simple, Electroplating… Rate Formula Module (RFM) Ion angular distribution function (IADF) Basic geometric modification – – – – – • Dry etch, Etchdepo, Etchdepo2, HDP, HDP2, Ion_enhanced, Ionmill, Rie, Rie2, Simple… Domain definition Truncation Mask handling Limited shape generation Material removal Interfacing – – Sentaurus Topography 3D – Sentaurus lithography Sentaurus Process – Sentaurus Topography 3D ©Synopsys 2012 7 Intermediate Surface Plots Watch relevant data on the surface during etching or deposition Intermediate data plots ©Synopsys 2012 8 Final shape Sentaurus Topography RFM: Ion-assisted Etch(IE) Equation • Using the Rate Formulation Method (RFM) allows the direct formulation of etch equations. • In this example: Etching of Silicon with Chlorine radical species (Fr) flux and ion fluxes (Fi) , scaling factor Ke, sticking coefficient Sr and the etching yield Y. The incident ion angle distribution (IAD) is defined by the user. π β Γπππ πΈπ = ππ π β Γπππ 1+ ππ β Γπ # Etch rate calculation Rate formula easily translated with a Tcl-like syntax into a command file. Fluxes are given by RFM module, yields and constants are defined by the user. ©Synopsys 2012 9 Topography to Process Coupling Stress effects during deposition von Mises Stress ©Synopsys 2012 10 Lithography ↔ Topography Value links between TCAD Sentaurus simulation tools Litho Etch Litho Etch (Mask 1) (hardmask) (Mask 2) (poly) • Sentaurus Lithography for simulation of 2D and 3D resist profiles, incl. LER • Sentaurus Topography 2D with chemical reaction modeling and reactive ion etching models • Sentaurus Topography 3D with empirical models (resolution and size limited) Applications • Double patterning techniques – process development • Vertical integration (e.g. FinFET) • Study impact of process effects and correction techniques • • • • LER Proximity effects Corner rounding with spacers Process variability • Links to device simulation ©Synopsys 2012 11 Spacer patterning for FinFET gate Resist after post-exposure bake and development (incl. LER) After etch Physical Topography Model Calibration Measurement Operating parameters •Flow rates •Pressure •Frequency •Temperature •Bias Plasma Simulation Etch recipe & Reactorgeometry Surface reaction model In Chamber Metrology •Current densities •Ion flux and ratio •Concentrations Etch Profile Measurement •SEM cross section •Etch rates •Etch yield Energy weighted Ion angle Distribution (EIAD) Etch Profiles ©Synopsys 2012 12 Feature Calibration Outline Sentaurus Topography 3D introduction SPTOPO3D project setup Input file for the built in Ionmill model Input file for the RFM sputtering model ©Synopsys 2012 13 Sentaurus Topography 3D 3D SWB Example • Sentaurus Topography integrated into Sentaurus Workbench (SWB) • This allows easy parameterization, interfacing and integration of the topography simulator with other tools SWB SPTOPO3D Parameters and associated values ©Synopsys 2012 14 Sentaurus Topography 3D 3D SWB Example Right click the Sentaurus Topography 3D icon Double click “commands…” Input file: 1. In case of RFM: 1. Model definition with RFM including e.g. ion reflection switched on 2. Definition of yields and constants values, reflection probabilities, etc. 2. Etch machine definition 3. Etching using defined etch machine ©Synopsys 2012 15 strings in format @string@ are SWB parameters. Outline Sentaurus Topography 3D introduction SPTOPO3D project setup Input file for the built in Ionmill model Input file for the RFM sputtering model ©Synopsys 2012 16 Ion Mill: Sputtering • Ions sputter material, no IAED information used • The sputter rate depends on the impact angle and is given by an yield function: ο§ (ο±im ) ο½ s1 cos ο±im ο« s2 cos 2 ο±im ο« s4 cos 4 ο±im 3 Yield function (arbitrary units) 2.5 nj 2 ο± 1.5 1 0.5 0 0 10 20 30 40 50 ο±ο° ©Synopsys 2012 17 60 70 80 90 Built-in Ionmill Model Example Simulation Results Resist Oxide Silicon Oxide Silicon ©Synopsys 2012 19 Outline Sentaurus Topography 3D introduction SPTOPO3D project setup Input file for the built in Ionmill model Input file for the RFM sputtering model ©Synopsys 2012 20 Feature-Scale Topography Simulation Reactor Scale Inputs: • Flow rates • Pressure • Temperature • Frequency Feature-Scale Plasma Inputs: Angular distibution and energy distribution of ions and neutral particles (IADF, IEDF) Wafer IAD and IED interface decouples feature scale from reactor scale ©Synopsys 2012 21 Sentaurus Topography 3D Flux Handling • Neutrals: Energy-independent fluxes with an isotropic angular distribution • Ions: Energy-dependent and energy-independent fluxes with an anisotropic angular distribution – Ion angular distributions (IAD) – Yield function – Reflection probability ©Synopsys 2012 22 RFM Sputtering etching Model Example Ion Angular Distribution Input Example 40 mTorr, 1 kW ICP, 0.3 kW Magnetron, -25 V dc bias, 100 V rf on coils with -90 V induced dc bias Quantemol-D Plasma Simulation ©Synopsys 2012 23 Integration of angular distributions over energies Ion Flux normalization Sentaurus Topography 3D RFM Flux Definition ... add_ion_flux model=my_model \ name=I reflection=true \ sputtering=true \ sputter_deposition=false \ energy=independent ©Synopsys 2012 24 RFM Sputtering etching Model Example Input File and settings • Sourcing the model definition, Yield table and the IAD table • Defining the model in use and its associated parameters • Setting the initial structure • Activating the etching model ©Synopsys 2012 25 Model definition Sputtering rate User-defined Normalized sputtering yield table User-defined IAD RFM Results Resist Oxide Oxide Silicon Silicon ©Synopsys 2012 27 ©Synopsys 2012 28
