Victory Process. Full Physical 3D Semiconductor Simulator Etching and Deposition Simulation

Transcription

1 Victory Process Full Physical 3D Semiconductor Simulator Etching and Deposition Simulation

2 Victory Process 3D Process Simulator Victory Process provides the capability to simulate comprehensive full process flows Etching, Deposition Oxidation, Stress Implantation Diffusion Self explanatory process flow description Open interface for modeling Model parameters and functions can be accessed and modified Open C-function library is used to implement the models Precompiled model library is provided - 2 -

3 Victory Process Level Set Framework The structure is represented as a set of implicit surfaces Hierarchical Cartesian meshes are used to improve the accuracy around critical areas Support for automatic and manual mesh refinement - 3 -

4 Victory Process Level Set Framework Very stable surface propagation algorithms Automatic void detection Avoids the problem of loops creation and correction - 4 -

5 Victory Process Etching / Deposition Modes Geometrical mode Numerical error is limited by the mesh size only Orders of magnitude faster than physical simulation of corresponding process Emulates a limited number of idealized processing steps Does not support shading effects Physical mode Simulates real physical processes Accurately handles complex shading and visibility effects Comprehensive set of models Can be extended via open modeling interface Slower than geometrical mode - 5 -

6 Victory Process Geometrical Mode Comprehensive mask support GDSII format masks lay format masks (MaskViews) Definition of mask polygons inside the processing deck Mask variations via the deck (shrink and expand) Selection of a simulation window - 6

7 Victory Process Geometrical Mode Lithography Calculation of aerial images Pattern transfer of aerial images Aerial Image Mask Layer Transferred Pattern - 7 -

8 Victory Process Geometrical Mode Geometrical etching Idealized directional mask pattern or image transfer Pattern transfer with tilted sidewalls and rounded corners Ideal Pattern Transfer With Tilted Sidewalls and Rounded Corners With Tilted Sidewalls - 8 -

9 Victory Process Geometrical Mode Geometrical etching Idealized wet and dry etching Selective and non-selective mode Wet Etching Initial Structure Dry Etching Wet Selective Etching - 9 -

10 Victory Process Geometrical Mode Geometrical CMP Idealized planarization Selective and non-selective mode Non-Selective Selective

11 Victory Process Geometrical Mode Geometrical deposition Idealized vertical resists or material regions defined by a mask Idealized conformal deposition Deposition of features with tilted sidewalls and rounded corners Planar mode to partially fill holes Conformal Deposition Planar Deposition

12 Victory Process Geometrical Mode - Summary Set of models for fast structure manipulation Based on idealized processing steps Used for Fast structure prototyping Creation of the initial shapes for subsequent physical analysis

13 Reactor-Scale vs. Feature-Scale The numerical engine of Victory Process only operates on the feature scale level Ballistic transport within the simulation domain is assumed Constant particle properties within the simulation domain are assumed Particle-particle interactions within the gas region are ignored Reactor scale conditions are an input to the simulation order of 10 um Wafer Reactor-Scale Feature-scale Simulation domain of Victory Process Substrate

14 Numerical engine : Calculates the amount of reactants reaching the surface from the reactor domain Takes into account secondary effects Re-deposition of removed material Reflection of reactants Calculates the surface propagation Open model library (accessible and extendible) : Provides information on particle fluxes coming from the reactor Specifies the distribution of particle re-emission and refection Determines how the mix of reactants at the surface affects the structure Local (for each surface point) etching or deposition rates are calculated

15 Boundary conditions : The structure is symmetrically and periodically extended in X and Y directions. This is necessary to properly take into account secondary effects. The number of 'reflections' depends on the desired redeposition accuracy Shading effects and visibility are taken into account for all 'reflections' Simulation domain

16 Etching models without particle flux Particle flux is not taken into account No visibility and shading effects are taken into account Selective etching capability Isotropic etching model Anisotropic etching model Selective Isotropic Etching Initial Structure Selective Anisotropic Etching

17 Deposition models without particle flux Particle flux is not taken into account No visibility and shading effects are taken into account Selective deposition capability Conformal deposition model Non-conformal deposition model Initial Structure Non-Conformal Selective Deposition

18 Etching and deposition models with a single primary particle Only the flux of a single particle coming from the reactor is taken into account Full consideration of visibility and shading effects The spacial velocity distribution of the particles coming from the reactor is an input to the model C-function in the open model library The spacial velocity distribution of the particles which are reflected from the surface is an input to the model C-function in the open model library The C-functions can be parametrized with parameters accessible through the input deck You can chose from a predefined set of distribution functions or create your own functions

19 Etching models with a single primary particle where surface reflection is neglected For these models a high sticking efficiency is implicitly assumed Hence surface reflection can be neglected Selective etching capability The etch rate is a linear function of the local particle flux Directional etching model Primary only etching model RIE etching model

20 Directional etching model Is a single primary particle etching model The velocity vector of all particles coming from the reactor is identical and by default perpendicular to the plane wafer surface Initial Structure Selective Directional Etching

21 Primary etching model Is a single primary particle etching model The spacial velocity distribution of the particles can vary from an isotropic distribution (default) to a highly focused distribution Width of the distribution function may be used as a parameter Isotropic Flux Initial Structure Cos 3 Flux Primary Etching Model Compared with Idealized Models

22 RIE etching model Is a single primary particle etching model The two physical particles (ion and neutral) are superimposed in one flux distribution This is possible because secondary fluxes are neglected and identical surface interaction (reaction) properties are assumed for both particles : rate is linearly proportional to the flux Particles are differentiated by the surface material In the model the incoming flux distribution depends on the surface material The RIE model is used for DRIE (Bosch) process simulation (etching cycle)

23 RIE etching model The spacial velocity distribution of the ions is highly focused Von Mises spacial velocity distribution is applied The standard deviation is used as a parameter The spacial velocity distribution of the neutral is isotropic Ratio between the two components (neutrals ions) on the plane surface is used as a parameter

24 RIE etching model Initial structure Etching with RIE Model Profile Sensitivity to RIE Model Parameters (ion focus, ion/neutral ratio)

25 Deposition models with a single primary particle where surface reflection is neglected For these models a high sticking efficiency is implicitly assumed Hence surface reflection can be neglected Selective deposition is possible Directional deposition model Primary only deposition model Ion beam deposition models

26 Directional deposition model Is a single primary particle deposition model The velocity vector of all particles coming from the reactor is identical and by default perpendicular to the plane wafer surface Particle direction may be used as a parameter Initial Structure Selective Directional Deposition

27 Primary deposition model Is a single primary particle deposition model The spacial velocity distribution of the particles can vary from an isotropic distribution (default) to a highly focused distribution Width of the distribution function may be used as a parameter Isotropic Flux Initial Structure Cos 3 Flux Primary Deposition Model Compared with Idealized Models

28 Ion beam deposition models Single primary particles are considered Static and rotating beams Beam can temporarily be switched off during rotation Ideally focused and Gaussian shape Beam with divergence Beam shape accessible via open model library Material specific, incident angle dependent deposition rate Tabulated rate functions accessible via open model library Specific convenient input deck statement

29 Ion beam deposition models Initial Structure Ion Beam Deposition With Single Directional Beam

30 Etching models with a single primary particle where surface reflection is taken into account Selective etching capability Material specific sticking efficiencies The etch rate is a linear function of the local particle flux Re-emission etching model

31 Re-emission etching model Is a single particle etching model Spacial primary velocity distribution of the particles can vary from an isotropic distribution (default) to a highly focused distribution Width of the distribution function may be used as a parameter Spacial velocity distribution of the reflected particles can vary from an isotropic distribution (default) to a highly focused distribution with preferential reflection direction

32 Re-emission etching model Initial Structure Selective Etching with Re-emission Etching Model Effect of Varying Sticking Efficiencies

33 Etching models with a single primary particle where emission of etched material is taken into account Ion Milling Etching Models Static and rotating beams Beam can be temporarily switched off during rotation Ideally focused or Gaussian beam shape Beam with divergence Beam shape accessible via open model library Material specific, incident angle dependent mill rate Tabulated mill rate functions accessible via open model library Mill rate functions derived from processing conditions by means of a semi-empirical model (implemented in open model library) Redeposition capability Multiple material may be redeposited forming an alloy Specific convenient input deck statement

34 Ion milling etching models beam direction Initial Structure Static beam Redeposition of alloy Selective deposition efficiency Material specific mill rate functions After Ion Milling

35 Deposition models with a single primary particle where surface reflection is taken into account Selective deposition capability The deposition rate is a linear function of the local particle flux Reemission deposition model

36 Reemission deposition model Is a single particle deposition model Spacial primary velocity distribution of the particles can vary from an isotropic distribution (default) to a highly focused distribution Width of the distribution function may be used as a parameter Spacial velocity distribution of the reflected particles can vary from an isotropic distribution (default) to a highly focused distribution with preferential reflection direction

37 Reemission Deposition Model Initial Structure Vary Sticking Efficiency Deposition with Re-emission Model

38 Advanced etching models with multiple primary particle Multiple primary particles Some particles may be reflected Material specific sticking efficiencies Material specific surface reaction properties IECE (Ion Enhanced Chemical Etching) model

39 Ion enhanced chemical etching model Two particle model where ions and neutral coming from the reactor are taken into account Neutrals Chemically active, uncharged particles Ions Accelerated charged particles Neutrals are chemically reacting at the surface with bulk atoms Reaction by-products are covering dangling bonds at the surface reduces the effective chemical conversion rate Reaction by-products are removed from the surface by desorption and ion sputtering

40 Ion enhanced chemical etching model e.g Silicon Etching in SFx Plasma F Ions SiFx removed by ions SiFx removed by desorption 1. The neutrals (F) chemically attach themselves to Si surface (dangling bonds) 2. Newly formed SiFx molecules cover the surface preventing further reaction 3. SiFx molecules are removed either by Natural desorption Ion sputtering (when present) This decreases the surface coverage Once residuals leave the surface, Si bonds can 'catch' F radicals again from ambient Ion flux increases the effective etch rate The model is fully implemented in the open model library

41 Ion enhanced chemical etching model Ions decrease the surface coverage at the bottom of the trench Trench aspect ratio increases with ion energy

42 Victory Process Summary Victory Process is a powerful tool for simulating 3D structure transformations by etching and deposition processes Command deck syntax based on technological processes Very robust numerical algorithms for geometrical transformations Ability for rapid structure prototyping using geometrical mode Numerical engine takes into account secondary effects Redeposition Re-emission Open model library for user-defined models Supplied with a range of predefined models Suitable for applications like Planar MOS, FinFET, Power devices, MEMS, Hard coating, Mass storage devices