VICTORY PROCESS Full Physical 3D Semiconductor Simulator Etching - - PowerPoint PPT Presentation

VICTORY PROCESS

Full Physical 3D Semiconductor Simulator Etching and Deposition Simulation

Full Physical 3D Semiconductor Simulator

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

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Full Physical 3D Semiconductor Simulator

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
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Full Physical 3D Semiconductor Simulator

VICTORY Process – Level Set Framework

• Very stable surface propagation algorithms
• Automatic void detection
• Avoids the problem of loops creation and correction
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Full Physical 3D Semiconductor Simulator

VICTORY Process – Etching / Deposition Modes

Geometrical Mode

+Numerical error is limited by the mesh size only +Orders

• f

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
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Full Physical 3D Semiconductor Simulator

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
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Full Physical 3D Semiconductor Simulator

VICTORY Process – Geometrical Mode

• Lithography
• Calculation of aerial images
• Pattern transfer of aerial images
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mask layer aerial image transferred pattern

Full Physical 3D Semiconductor Simulator

VICTORY Process – Geometrical Mode

• Geometrical Etching
• Idealized directional mask pattern or image transfer
• Pattern transfer with tilted sidewalls and rounded corners
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ideal pattern transfer with tilted sidewalls with tilted sidewalls and rounded corners

Full Physical 3D Semiconductor Simulator

VICTORY Process – Geometrical Mode

• Geometrical Etching
• Idealized wet and dry etching
• Selective and non-selective mode
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dry etching wet selective etching wet etching initial structure

Full Physical 3D Semiconductor Simulator

• Geometrical CMP
• Idealized planarization
• Selective and non-selective mode
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Selective Non-Selective

VICTORY Process – Geometrical Mode

Full Physical 3D Semiconductor Simulator

• 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
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VICTORY Process – Geometrical Mode

Conformal Deposition Planar Deposition

Full Physical 3D Semiconductor Simulator

• Set of models for fast structure manipulation
• Based on idealized processing steps
• Used for

 fast structure prototyping and  to create the initial shapes for subsequent physical analysis

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VICTORY Process – Geometrical Mode - Summary

Full Physical 3D Semiconductor Simulator

• 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

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VICTORY Process – Physical Mode Reactor-Scale vs. Feature-Scale

Substrate

• rder of 10 um

Reactor-Scale Wafer Feature-scale Simulation domain

• f VICTORY Process

Full Physical 3D Semiconductor Simulator

• 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

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VICTORY Process – Physical Mode

Full Physical 3D Semiconductor Simulator

• Boundary Conditions :

 The structure is symmetrically and periodically extended in X and Y

• directions. This is necessary to properly take into account secondary

effects.

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VICTORY Process – Physical Mode

Simulation domain

• The number of 'reflections' depends on the

desired redeposition accuracy

• Shading effects and visibility are taken into

account for all 'reflections'

Full Physical 3D Semiconductor Simulator

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

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VICTORY Process – Physical Mode

selective anisotropic etching selective isotropic etching initial structure

Full Physical 3D Semiconductor Simulator

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

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VICTORY Process – Physical Mode

Conformal Selective Deposition Non-Conformal Selective Deposition

initial structure

Full Physical 3D Semiconductor Simulator

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

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VICTORY Process – Physical Mode

Full Physical 3D Semiconductor Simulator

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 PrimaryOnly Etching Model RIE Etching Model

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VICTORY Process – Physical Mode

Full Physical 3D Semiconductor Simulator

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

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VICTORY Process – Physical Mode

initial structure selective directional etching

Full Physical 3D Semiconductor Simulator

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

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VICTORY Process – Physical Mode

initial structure

Isotropic Flux Cos3 Flux

primary etching model compared with idealized models

Full Physical 3D Semiconductor Simulator

 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)

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VICTORY Process – Physical Mode

Full Physical 3D Semiconductor Simulator

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

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VICTORY Process – Physical Mode

Full Physical 3D Semiconductor Simulator

RIE Etching Model

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VICTORY Process – Physical Mode

initial structure profile sensitivity to RIE model parameters (ion focus, ion/neutral ratio) etching with RIE model

Full Physical 3D Semiconductor Simulator

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 PrimaryOnly Deposition Model Ion Beam Deposition Models

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VICTORY Process – Physical Mode

Full Physical 3D Semiconductor Simulator

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

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VICTORY Process – Physical Mode

initial structure selective directional deposition

Full Physical 3D Semiconductor Simulator

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

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VICTORY Process – Physical Mode

initial structure

Isotropic Flux Cos3 Flux

primary deposition model compared with idealized models

Full Physical 3D Semiconductor Simulator

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

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VICTORY Process – Physical Mode

Full Physical 3D Semiconductor Simulator

Ion Beam Deposition Models

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VICTORY Process – Physical Mode

initial structure ion beam deposition with single directional beam

Full Physical 3D Semiconductor Simulator

 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

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VICTORY Process – Physical Mode

Full Physical 3D Semiconductor Simulator

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

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VICTORY Process – Physical Mode

Full Physical 3D Semiconductor Simulator

Re-emission Etching Model

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VICTORY Process – Physical Mode

initial structure Effect of varying sticking efficiencies selective etching with re-emission etching model

Full Physical 3D Semiconductor Simulator

 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

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VICTORY Process – Physical Mode

Full Physical 3D Semiconductor Simulator

 Ion Milling Etching Models

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VICTORY Process – Physical Mode

initial structure after ion milling

beam direction

Static beam Redeposition of alloy Selective deposition efficiency Material specific mill rate functions

Full Physical 3D Semiconductor Simulator

 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

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VICTORY Process – Physical Mode

Full Physical 3D Semiconductor Simulator

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

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VICTORY Process – Physical Mode

Full Physical 3D Semiconductor Simulator

Reemission Deposition Model

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VICTORY Process – Physical Mode

initial structure deposition with reemission model vary sticking efficiency

Full Physical 3D Semiconductor Simulator

 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

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VICTORY Process – Physical Mode

Full Physical 3D Semiconductor Simulator

• 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

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VICTORY Process – Physical Mode

Full Physical 3D Semiconductor Simulator

 Ion Enhanced Chemical Etching Model

• e.g Silicon Etching in SFx Plasma
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VICTORY Process – Physical Mode

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

Full Physical 3D Semiconductor Simulator

 Ion Enhanced Chemical Etching Model

• Ions decrease the surface coverage at the bottom of the trench

→ Trench aspect ratio increases with ion energy

VICTORY Process – Physical Mode

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Full Physical 3D Semiconductor Simulator

 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

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VICTORY Process – Summary