PLASMA EQUIPMENT MODELING FOR PROCESS DESIGN*

VMIC0001

PLASMA EQUIPMENT MODELING FORPROCESS DESIGN*

Mark J. KushnerUniversity of Illinois

Department of Electrical and Computer EngineeringUrbana, IL 61801

http://uigelz.ece.uiuc.edu

June 2000

*Work supported by: NSF, SRC and DARPA/AFOSR

AGENDA

VMIC0007

University of Illinois Optical and Discharge Physics

• Goals and requirements for Plasma Equipment and Process Modeling

• A "Walk-Through" of plasma properties for ICP conductor etching.

• Overview of Modeling Hierarchy

• Profile Control for Etching and Deposition

• Concluding Remarks

PLASMAS AND INTERCONNECT FABRICATION

VMIC0003


• The majority of the processes which enable fabrication of advancedinterconnect structures are based on plasma processing (etching,deposition, cleaning).

Ref: IBM Microelectronics

PLASMAS IN MICROELECTRONICS FABRICATION

ICOPS00_06


• Plasmas play a dual role in microelectronics fabrication....

• First, electron impact on otherwise unreactive gases produces neutralradicals and ions. That is, electrons are a power transfer medium.

ELECTRODE

PLASMA REACTOR

NON-REACTIVE GAS FLOW

PRODUCT REMOVAL

e + CF 4 → CF3+ + F + 2e

→ CF 2 + 2F + e

Si WAFER

CF 3+

FSiF 2CF 4 SiF 4

• These active species drift or diffuse to the wafer where they remove ordeposit materials.

PLASMAS IN MICROELECTRONICS FABRICATION

ICOPS00_06


• Second, ion acceleration in sheaths delivers directed activation energy tosurfaces which enables fine features to be fabricated having extreme andreproducable tolerances.

PLA

SM

A P

OT

EN

TIA

L

POSITION

WAFER

SHEATH

+ION

IONS

MASK

SiO 2

Si

• Ion Assisted Etching • Neutral Dominated Etching

NEUTRAL RADICALS

0.25 µµm Feature(C. Cui, AMAT)

APPLIED MATERIALS DECOUPLED PLASMA SOURCE (DPS)_______________________________________________

__________________University of Illinois

Optical and Discharge PhysicsCECAM9826

MOTIVATION FOR PLASMA EQUIPMENT/PROCESS MODELING

VMIC0004


•• As fab construction costs increase well beyond $1 Billion, a largerproportion of the costs are consumed by processing equipment.

• The motivation forplasma equipment andprocess modeling isthen:

• Reduce the cost ofdeveloping equipmentand processes.

• Increase utilization ofequipment to addressmultiple processes.

TYPICAL PLASMA PROCESSING REACTOR

ICOPS00_07


• The typical low pressure (<10s - 100s mTorr) plasma processing reactor ispowered by inductive and capacitive coupling, and may have auxiliarystatic magnetic fields.

PUMP PORT

DOME

GAS INJECTORS

BULK PLASMA

WAFER

30 30 0

RADIUS (cm)

HE

IGH

T (

cm)

0

26

sCOILS

s

rf BIASED SUBSTRATE

SOLENOID

POWER SUPPLY

POWER SUPPLY

WALK THROUGH: Ar/Cl2 ICP TOOL

AMATET_0500_09


• The general properties of an Ar/Cl2 inductively coupled plasma tool will beexamined.

• The inductively coupledelectromagnetic fields havea skin depth of 3-4 cm.

• Absorption of the fieldsproduces power depositionin the plasma.

• Electric Field (max = 6.3V/cm)

• Ar/Cl2 = 80/20• 20 mTorr• 1000 W ICP• 250 V bias, 2 MHz (260 W)

Ar/Cl2 ICP TOOL: POWER AND ELECTRON TEMPERATURE

AMATET_0500_10


• Power deposition from the inductive fields results in electron heating.• At 2 MHz, power from the capacitive fields produces ion acceleration with

little electron heating.

Power Deposition (max = 0.91 W/cm3) Electron Temperature (max = 5 eV)

• Ar/Cl2 = 80/20, 20 mTorr, 1000 W ICP, 250 V , 2 MHz bias (260 W)

Ar/Cl2 ICP TOOL: IONIZATION

AMATET_0500_11


• Electron impact ionization by the bulk electrons heated by the inductivelycoupled fields dominates.

• Ionization by sheath accelerated beam electrons is less important due totheir long mean-free-paths at the low operating pressure.

Beam ionization (max = 1.3 x 1014 /cm3-s) Bulk ionization (max = 5.4 x 1015 /cm3-s)


Ar/Cl2 ICP TOOL: POSITIVE ION DENSITY

AMATET_0500_12


• The diffusion of plasma from the remote sources produces a fairlyuniform positive ion density in the vicinity of the substrate.

• In general, better uniformity is obtained with a bias than without.

Positive Ion Density(max = 1.8 x 1011 /cm3-s)


Ar/Cl2 ICP TOOL: BIAS CURRENTS, POTENTIALS

ICOPS00_14


2 MHz SUBSTRATE

PO

TE

NT

IAL

(V

)

• The small currentcollection area of thesubstract produces alarge negative dc bias

• The large sheathpotential results inelectron current beingcollected during a smallfraction of the rf cycle.

• The non-linearity of thesheaths at differentsurfaces also contributesto the non-sinusoidalcurrent.

• Ar/Cl2 = 80/20, 20 mTorr,1000 W ICP, 250 V , 2 MHzbias (260 W)

PHYSICS TO BE ADDRESSED

ICOPS00_08


PUMP PORT

GAS INJECTORS (fluid dynamics)

BULK PLASMA (plasma hydrodynamics, kinetics,

chemistry, electrostatics,electromagnetics)

WAFER

30 30 0

RADIUS (cm)

HE

IGH

T (

cm)

0

26

sCOILS (electro-

magnetics)

s

rf BIASED SUBSTRATE

SOLENOID (magnetostatics)

DOME (suface chemistry, sputter physics)

POWER SUPPLY (circuitry)

POWER SUPPLY (circuitry)

POLYMER (surface chemistry, sputter physics)

M+ e

Secondary emission (beam physics)

WAFER

E-FIELD (sheath physics)

PROFILE EVOLUTION (surface chemistry,

sputter physics, electrostatics)

UNIVERSITY OF ILLINOISOPTICAL AND DISCHARGE PHYSICS

SPATIAL SCALES IN PLASMA PROCESSING SPANMANY ORDERS OF MAGNITUDE

ICRP97M12

• EQUIPMENT SCALE (cm - 10s cm)Gas FlowHeat TransferPlasma TransportChemical Kinetics

PLASMA

WAFER

e + CF4 > CF3+ + F + 2e

• FEATURE SCALE” (10s nm - µm)Electron, Ion, Radical TransportPlasma Surface InteractionSurface chemistry

IONS

SHEATH0.1 - 0.5 µm

WAFER

• “TRANSITION SCALE” (10s -100s µm)Electron and Ion TransportSparse CollsionsElectrodynamics

WAFER

SHEATH

SUBSTRATE

10’s - 100s µm

IONS

PLASMA

REQUIREMENTS TO MEET MODELING GOALS

AMATET_0500_04


• Robust, geometrically flexible simulator to address a wide range of tooltypes and operating conditions.

• Sufficient dynamic range in space and time to resolve phenomena ofinterest.

• Databases of fundamental atomic and molecular data to for processrelevant chemistries.

• Understanding of limits and proper uses of modeling so that expectationsand return-on-investment are realistic.

PLASMA EQUIPMENT MODELING HIERARCHY


SRCRM9801

HYBRID PLASMAEQUIPMENT MODEL (HPEM)Charged Particle and Neutral densities

Ion and Neutral FluxesElectron Energy DistributionsElectric Fields and Potentials

Plasma ChemistryElectrical Circuitry

PLASMA CHEMISTRYMONTE CARLO SIMULATION

(PCMCS)Ion and Neutral Energy DistributionsIon and Neutral Angular Distributions

Plasma chemistry

MONTE CARLO FEATUREPROFILE MODEL (MCFPM)

Etch / Deposition Feature ProfilesSurface Chemistry

DUST TRANSPORTSIMULATION (DTS)Dust Particle Trajectories

Particle Contamination of Surfaces

DUST PARTICLEAGGLOMERATION MODEL

(DPAM)Dust Particle TransportParticle Agglomeration

DUST PARTICLE GROWTHMODEL (DPGM)Dust Particle Transport

Particle Nucleation and Growth

Available now to SRC andSematech MemberCompanies; others byArrangement

Available By Request

ELECTROMAGNETICS

ICOPS00_10


• The wave equation is typically solved in the frequency domain:

( ) ( )t

JE

t

E E E

2

∂

+∂+

∂

∂=

∇⋅∇+

⋅∇∇−

σεµµ 211

r r r r rE r t E r i t r( , ) ( )exp( ( ( )))= ′ − +ω ϕ

σ

νω

ν

=

−

∑q n

mi

j

j jj

j

2

1

• With static applied magnetic fields, conductivities are tensor quantities:

( )m

e2

om

2z

2zrzr

zr22

rz

zrrz2r

2

22m

o

m

nq,

m/qi

Ej

BBBBBBB

BBBBBBB

BBBBBBB

B

1

q

m

νσ

νωασ

ααα

ααα

ααα

ααν

σσ

θθ

θθθ

θθ

=+

=⋅=

++−+−

+++−

+−++

+

=

r&&&

v

r&&&

•• Circuit models are used to provide antenna currents.

ELECTRON ENERGY TRANSPORT

ICOPS00_11


• Under conditions where collisional heating and diffusive transportdominate, electron transport coefficients and electron impact sourcefunctions are obtained by solving the electron energy equation.

( ) ( ) ( ) EBeeeeeee

STTkT25

TLTSt

kTn23

+

∇−Φ⋅∇−−=

∂

∂

κ

where S(Te) = Power depositionL(Te) = Electron power loss due to collisionsΦΦ = Electron fluxκκ(Te) = Electron thermal conductivitySEB = Electron source from beam electrons

• Transport coefficients are obtained as a function of average energy (εε =(2/3) Te) from solution of Boltzmann' Equation for the electron energydistribution.

ELECTRON ENERGY TRANSPORT

ICOPS00_11


• When electron energy deposition is non-collisional and/or transport isnon-diffusional, Monte Carlo techniques are used.

• Secondary electron emission and acceleration through sheaths.

• Wave heating and trapping.

• Long mean-free-path transport.

• Conduction currents are kinetically derived from the MCS for use insolving the wave equation.

Je(r) = J0(r) exp(iφv(r)) $θθ = –q ne(r) vθ(r) exp(iφv(r)) $θθ .

PLASMA CHEMISTRY, TRANSPORT AND ELECTROSTATICS

ICOPS00_12


• Multi-fluid techniques are used where continuity, momentum and energyequations are solved for each species, with coupling terms for exchangeof momentum and energy.

iiii S)vN(

t

N+⋅−∇= r

∂∂

( ) ( ) ( ) ( ) iii

iiiiiii

i

ii BvEm

NqvvNTkN

m

1

t

vNµ

∂∂

⋅∇−×++⋅∇−∇=rrrrr

r

( ) ijjijj

ijmim

jvvNN

mνrr −∑−

+

( ) 222

ii

i2ii

iiiiiiii E

)(m

qN)UN(UPQ

tN

ων

νε

∂ε∂

+=⋅∇+⋅∇+⋅∇+

∑±∑ −+

++j

jBijjij

ijBijjiji

ij2s

ii

2ii

TkRNN3)TT(kRNNmm

m3E

m

qN

ν ,

•• Slip boundary conditions are used for neutral transport for momentum andenergy to address momentum and temperature jump conditions.

PLASMA CHEMISTRY, TRANSPORT AND ELECTROSTATICS

ICOPS00_12


• Given the hierarchy of time scales and large number of species, fullyimplicit solutions of all transport equations are typically not done.

• Due to the extremely short dielectric relaxation times (<< 10-12 s), Poisson'sequation must be implicitly solved.

• A typical method uses a prediction of densities for the time at which thefields will be used. Surface charges are included here.

( ) ( )

∑ ⋅∇⋅∆∑+=∆+Φ∇⋅∇i

iii

iis qt-Nq-tt φρεr

• When sheaths are not resolved by the mesh, semi-analytic models areused to obtain sheath potentials, which are inserted as potential "jump-conditions" at surfaces.

CIRCUIT MODELS

ICOPS00_13


• Circuit models for the reactor and driving electronics provide voltageharmonics (amplitude and phase) on metal surfaces for solution ofPoisson's equation.

Sheath 1 Sheath 2 Sheath N

RC1

CC1

LC1

RB1

CB1

VS1

LB1

RA1

CA1

LA1

RB2

CB2

VS2

LB2

RA2

CA2

LA2

RBN

CBN

VSN

LBN

RAN

CAN

LANRCN-1

CCN-1

LCN-1

REACTOR

• Sheath models are typically employed to account for non-linearities in theplasma response to harmonic excitation.

• The MCFP model predicts time and spatially dependent etch profiles using neutral and ion fluxes from the PCMCS.

• Any chemical mechanism may be implemented in the MCFP using a "plasma chemistry" input hierarchy.

e.g., Cl+ + SiCl2(s) > SiCl2(g)

• All pertinent processes can be included: thermal etch, ion assisted etch, sputter, redeposition, passivation.

• Energy dependent etch processes may be implemented using parametric forms.

• The MCFP may utilize ALL flux statistics from the PCMCS

• Ion energy and angular distributions• Neutral energy and angular distributions• Position dependent fluxes

MONTE CARLO FEATURE PROFILE MODEL (MCFP)

Resist

p-Si

SiO2

Cl

Ar

Cl2

Cl+


CECAM98M16

SiClx

"Passivation"

Side-wallPassivation

Ar+Cl2+

PROFILE CONTROL FOR INTERCONNECT: ETCH AND DEP

VMIC0006


FLUOROCARBON ETCHING OF DIELECTRICS

IONIZED METAL PVD OF COPPER

FLOUROCARBON PLASMA ETCHING OF SiO2

AMATET_0500_18


• Fluorocarbon etching of SiO2 relies on a complex chemistry comprised ofpolymerization and chemically enhanced sputtering.

• Growth of CxFy passivation layer (balance of deposition andconsumption)

• Formation of a complex at the interface between oxide and passivationlayer resulting from chemisorption of CFx.

• Ion activated (through polymer layer) etching of complex in a two stepprocess. Activation scales inversely with passivation layer thickness.

• Diffusion of etch precursor and etch product through layer.

CFx

SiO2 SiFx

F

CF4

F

SiF4

Film Growth

•Film Etching

F

Etch

DiffusionCxFy

Passivation Layer

Ι+

CFx

CO2

SiO2 SiFxCO2 SiFx

CFx

Ι+CO2

Ι+, FEnergyTransfer

Etch

Plasma

SiO2

CF4

SiF4

F

CFx

Sputtering


C2F6 ETCH OF SiO2

DA-SRC99-04

• The SKM was used to investigate the C2F6 etching of SiO2 in an ICP reactor.

Radius (cm)

• C2F6, 10 mTorr, 100 sccm,

650 W ICP, 100 V bias.

• Electron Density • Representative gas phase chemistry:

e + C2F6 > CF3+ + CF3 + e + e

e + C2F6 > CF3- + CF3e + CF3 > CF2 + F + e

e + CF3 > CF2 + F-

e + CF3 > CF3+ + e + ee + CF4 > CF2 + F + F + eF + F + M > F2 + MCF2 + F2 > CF3 + FCF3 + F2 > CF4 + FCF3 + F > CF4 CF2 + F > CF3

ETCH RATE vs SUBSTRATE BIAS

VMIC0005


• In SiO2 etching, passivation is a requirement and a hinderance.• CFx is required as a precursor for removal of oxygen in the oxide.• Passivation slows the delivery of activation energy to the surface.

• At low bias, the passivation decreases with increasing bias due to ionsputtering, etch rate increases due to higher activation power to surface.

• At high bias, the process is passivation starved and the etch rate saturates.

Solid: ΓΓn / ΓΓi = 35Dashed: ΓΓn / ΓΓi = 25

C2F6, 10 mTorr, 100 sccm,650 W ICP

TAPERING OF PROFILES

AMATET_0500_19


• In high aspect ratio (AR) etching of SiO2 by fluorocarbon plasmas, the sidewall oftrenches are passivated by neutrals (CFx, x ≤ 2) due to the broad angulardistributions of neutral fluxes.

• Tapered trench profiles are produced when the passivation/ion flux ratio is large.

8

• Ar/C2F6 = 20/80.

• 1000 W ICP power,150 V bias.

• 10 mTorr.

• Radial location: 3 cm.

Experiment (C. Cui, AMAT) Simulation

0.25 um0.25 um

AR = 10:1 AR = 10:1

SiO2SiO2

PASSIVATION/ION FLUX RATIO

SRC2000-DA-15


• Increasing passivating neutral to ion flux ratio (Γn/Γion) leads to more taperedprofiles due to increasing sidewall passivation.

• When the passivating neutral flux is too small, insufficient sidewall protection bythe passivation layer leads to a bowed profile.

100% 125% 150% 175%

Bowed Straight Tapered Tapered

Normalized Γn/Γion

PR

SiO2

PASSIVATION/ION FLUX RATIO (cont.)

SRC2000-DA-16


• The bottom critical dimension of the trench decreases with increasing passivatingneutral to ion flux ratio (Γn/Γion).

• The SiO2 etch rate also decreases with increasing neutral flux due to increasingpassivation.

Normalized Γn/Γion

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

1 1.2 1.4 1.6 1.8

b / W

t

µm)

Wb: Trench width 0.5 um above the bottom.

Wt: Trench width at the top.

Depth: Trench depth after equal etch time steps.

Depth

Wb/Wt

Wt

De

pth

Wb

INFLUENCE OF ION ENERGY

SRC2000-DA-17


• With increasing ion energy, the increasing ion sputtering yield of the sidewallpassivation layer produces a less tapered profile.

• The etch rate also increases with increasing ion energy due to decreasing (butsufficient) passivation.

• Simulations and experiments obtained similar trends.

Experiments (C. Cui, AMAT) Simulations

800 W 1000 W 150 V 180 VBias Power

SiO2 SiO2

Bias Voltage

INFLUENCE OF ION ENERGY (cont.)

SRC2000-DA-18


• When the ion energy is very high, the SiO2 etching is limited by the ion flux instead ofthe ion sputtering yield.

• The etch rate and the bottom width of the trench are saturated at high ion energies.

Wb: Trench width 0.5 um above the bottom.

Wt: Trench width at the top.

Depth: Trench depth after equal etch time steps.

Wb/Wt

Depth

Wb / W

t

Depth

(µm

)

Wt

De

pth

Wb0.0

0.2

0.4

0.6

0.8

1.0

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

1.0 1.2 1.4 1.6 1.8 2.0150 300270240210180

Substrate Bias (V)

IONIZED METAL PHYSICAL VAPOR DEPOSITION

ICOPS00_24


• Ionized Metal PVD (IMPVD) is being developed to fill deep vias and trenchesfor interconnect, and for deposition of seed layers and diffusion barriers.

• In IMPVD, a second plasma source is used to ionize a large fraction of thesputtered metal atoms prior to reaching the substrate.

TARGET (Cathode)

MAGNETS

ANODE SHIELDS

PLASMA ION

WAFER

INDUCTIVELY COUPLED COILS

SUBSTRATE

S

SECONDARY PLASMA

BIAS

Ar+ + M > Ar + M+

e + M > M+ + 2e

NEUTRAL TARGET ATOMS

+

Typical Conditions:

• 10’s mTorr Arbuffer

• 100s V bias ontarget

• 100s W - kW ICP

• 10s V substratebias


ICOPS00_24


• In Physical Vapor Deposition (PVD), the majority of the metal flux to thesubstrate is neutral, having a broad angular distribution. This leads tononconformal deposition and creation of voids.

NEUTRALMETAL ATOMS

SiO2

METAL

VOID

PARTIALLY IONIZEDMETAL FLUX

SiO2

METAL

SRF BIAS

PHYSICAL VAPOR DEPOSITION


• In IMPVD, the addition of anisotropic metal ions to the flux producesconformal deposition by anisotropic filling and sputtering of overhangs.

PVD/IMPVD OF Cu: REACTOR LAYOUT_______________________________________________

__________________University of Illinois

Optical and Discharge PhysicsAFOSR9912

•• PVD/IMPVD reactor with Cu Target

• 3.5- 20 mTorr Ar (constant pressure), 150sccm

• Annular magnetic field (200 G below target• Target: -200 V dc (2.4 kW)• Substate: 40 V, 10 MHz, 350 W• Coils: 2 MHz, 1250 W with Faraday shield

• Physics included:

• Gas heating by sputtered target atoms• Ion energy dependent sputter yield• Neutral and ion momentum and energy• Bulk electron energy equation• Monte Carlo secondary electrons• Cross field Lorentz forces


IMPVD TOOL: FIELDS AND TEMPERATURES

CECAM98M07

• Ar, 20 mTorr• -200 V Target, 200 G• 1.25 kW ICP, 2 MHz

• The added inductively coupled electric field from the rf coils heats electrons in the bulk plasma producing a peak in temperature away from the target.

• Electron Temperature• Electric field


IMPVD TOOL: ELECTRON SOURCE AND DENSITY

CECAM98M08


• The combination of the magnetron fields and heating from the rf coils produces a more extended electron source and electron density. The ion density is 75% argon.

• Electron Density• Electron Source • Ar+


IMPVD TOOL: ION FLUX AND SPUTTER SOURCE

CECAM98M09


• The magnetron focus the ion flux to the target, producing a sputter source of Cu atoms.

• Due to the high gas pressure, the Cu atoms are thermalized in the vicinity of the target.

• Cu Source

• Ion Flux


IMPVD TOOL: Cu DENSITIES

CECAM98M10


• Due to the longer residence time of Cu in the chamber and the higher electron temperature produced by the rf heating, the Cu inventory is largely converted to ions and metastables [Cu(2D)].

• Cu(2S) • Cu(2D) • Cu+


TRENCH FILLING VS PRESSURE

JLU_ICOPS00_11

• *Operating conditions:

• 1 kW ICP • 0.3 kW magnetron• -25 V dc bias on wafer

• Voids form at low pressure. The voids fill with increasing pressure and fill at 40 mTorr.

• The ionization fraction of increases with increasing pressure, due to slowing of Cu atoms which allows more ionization. • Reasons for pinch-off:

• Diffuse angular distribution of the neutrals

• Less sputtering of over-hanging deposits

*Cheng, Rossnagel and Ruzic, JVST B 13, 203 (1995).

Width (µm)

0 0.4 0.8 1.2

0.8

0.4

0

1.2

Cu+ : Cu Neutrals = 1:3 4:12:1

5 mTorr 20 mTorr 40 mTorr

600 nm

Width (µm)

0 0.4 0.8 1.2

Width (µm)

0 0.4 0.8 1.2

5 mTorr 20 mTorr 40 mTorr

TRANSITION FROM PVD TO IMPVD

ICOPS00_20


• With increasing ICP power deposition, a larger proportion of the Cu metalflux striking the substrate is ionized.

• The end result is conformal trench filling and elimination of the void.ICP Power = 0.3 kW

Cu+ : Cu Neutrals = 1.4:1

Width (µm)0 0.4 0.8 1.2

Hei

ght (

µ m) 0.8

0.4

0

1.2

Width (µm)0 0.4 0.8 1.2

Width (µm)0 0.4 0.8 1.2

0.6 kW 2.5:1

1.0 kW 3.0:1

• Ar 30 mTorr, 300 W Magnetron, -30 V bias

IMPORTANT PHYSICS, METHODS, STATUS

AMATET_0500_05


• Further improvements in plasma equipment modeling will requireimprovements in both methods and availability of fundamental data.

PHENOMENON TOOLTYPE

EQUATIONS &METHODS

STATUS

Electromagnetics ECR, ICPHELICONHFCCP

Maxwell Eqs. Robust solvers available.Time domain is difficult.

Magnetostatics MERIEPVD

HELICON

Maxwell Eqs. Robust solvers available.

Electrostatics ALL Poisson's Eq. Better implicit solversare needed.Very high bias, magneticfields difficult.

Electron EnergyTransport

ALL Monte Carlo,Fluid Eqs.

Robust solvers whichare computationallyefficient are required.High magnetic fieldsdifficult.

IMPORTANT PHYSICS, METHODS, STATUS

AMATET_0500_05


PHENOMENON TOOLTYPE

EQUATIONS &METHODS

STATUS

Neutral and IonTransport

ALL Compressible,multi-fluid NavierStokes

Robust solvers available.High magnetic fieldsdifficult.Long term transientsdifficult.

Sheath Physics ALL Semi-analyticmodels

Physics understood butdifficult to implement for"harsh" conditions.

Long Mean FreePath Transport

PVD,ECR

Monte Carlo,Greens Function

Robust methods whichtake large CPU time.

Surface Chemistry ALL Multi-layersurface site-balance

Robust solvers available.Limited by availability offundamental data.

Profile Evolutions ALL Monte Carlo,Level set, Stringmethods

Robust solvers available.Charging modelsuncertain.Limited by availability offundamental data.

CONCLUDING REMARKS

AMATET_0500_21


• Plasma equipment modeling has developed to the point that quantitativedesign of tools can be performed and the design cycle can be shortened.

• Process design based on modeling is in a more qualitative state, thoughprogress is being made.

• Significant improvements are required in our databases of fundamentalparameters (e.g., cross sections) so that more complex plasmachemistries can be addressed.

VMIC0002

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PLASMA EQUIPMENT MODELING FOR PROCESS DESIGN*

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