sustaining another decade of innovation...

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SUSTAINING ANOTHER DECADE OF INNOVATION INEQUIPMENT AND PROCESS DESIGN: NEEDS AND

CHALLENGES*

Mark J. KushnerUniversity of Illinois

Department of Electrical and Computer EngineeringUrbana, IL 61801

http://uigelz.ece.uiuc.edu →→ "Presentations" link

October 2000

* Work supported by NSF, SRC, DARPA/AFOSR

AGENDA

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University of Illinois Optical and Discharge Physics

• Reflection on 10 years past...

• ITRS Requirements

• Knowlegebase Generation

• The "challenge": Smart, Aware and Proactive Tools

• Examples of SAP Tools

• New systems and materials

• Concluding Remarks

QUALIFICATIONS TO GIVE THIS TALK....

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37th AVS INTERNATIONAL SYMPOSIUMOctober 1990, Toronto, Canada

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Topics from papers appearing in Proceedings of 37th AVS InternationalSymposium

Plasma Sources:

Helicon 1 ECR 10RIE 8 Magnetron 1ICP 0 Ion Beam 1

Materials:

Polymer 2 SiGe 1Si3N4 1 p-Si/c-Si 3SiO2 2 GaAs 1

JVST A 9, 722 (1991)

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• Cl2 plasma

• Measurements of ion energies arriving at the substrate correlate with peakplasma potential, indicating collisionless acceleration through (pre)sheath.

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• Laser lightscattering frompatterned wafersis spatiallyanayzed as asensor forfeature shape.

Quantification of surface film formation effects in fluorocarbon plasmaetching of polysilicon

David C. Gray and Herbert H. SawinDepartment of Chemical Engineering, MIT, Cambridge Massachusetts 02139

Jeffrey W. ButterbaughIBM, General Technology Division, Essex Junction, Vermont 05452 JVST A 9, 779 (1991)

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• Radical/ion beams synthesize the plasma tool environment and show adecrease in p-Si etching with CF2/Ar+ ratio due to overlying polymerization.

CHALLENGES FOR < 100 nm BEYOND 2005

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• ITRS cites many "no known solutions" for interconnect to meet the 55 nmtechnology node by 2011.


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• The challenges cited to meet the ITRS goals focus on new materials andstructures.

Int. Tech. Roadmap Semi.: Interconnect 1999


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• Potential solutions foretch emphasize newmaterials, high plasmadensity sytems andcleans.

MARKETS AND APPLICATIONS

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• With the advent of high speed networks and parallel computing, pastspecialized markets for logic have collapsed to a single line.

• As processing becomes more critical (expensive) at <100 nm nodes andapplications return to centralized computing, the market may bifurcate.

HIGH-PERFORMANCE (MAINFRAMES)

MID-PERFORMANCE (MINI'S)

LOW-PERFORMANCE (MICRO'S)

COMMODITY (CONTROLLERS)

COMPOUND MAT'LS (LASERS)

EXTREME-PERFORMANCE (MAINFRAMES,

SERVERS)

HIGH-PERFORMANCE (DESKTOP)

COMPOUND MAT'LS (LASERS,

COMMUNICATION)

MEMS (SENSORS,

ACTUATORS)

SYSTEM ON CHIP, SMART WAFERS, SELF ASSEMBLY

THEN NOW TO COME

• MEMS, compoundmaterials (e.g.,Si/Ge) andorganics will join"conventional"silicon insensors, HBTs,actuators, SOCand opticalinterconnect.

"GENERIC" PLASMA PROCESSING REACTOR

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• For purposes of illustration during this talk, a "generic" plasmaprocessing reactor will be used to demonstrate principles.

PUMP PORT

DOME

GAS INJECTORS

BULK PLASMA

WAFER

30 30 0 RADIUS (cm)

HE

IGH

T (c

m)

0

26

sCOILS

s

rf BIASED SUBSTRATE

SOLENOID

POWER SUPPLY

POWER SUPPLY

INNOVATION REQUIRES MASTERY OF THE BASICS

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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)

THE PROBLEM....

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• Uniformity and control of reactants becomes increasingly more difficult aswafer sizes increase and process chemistries become more complex.

• For example, non-uniformities in ion flux (sheath edge plasma density)across a wafer produce a change in sheath thickness and acommensurate change in ion energy-angular distributions.

RADIUS (cm)

SH

EA

TH

TH

ICK

NE

SS (

µ m)

SHEATHFLUX

ION

FLU

X (

1016

/cm

2 -s)

RADIUS (cm)

ION DENSITY

-12 120 -12 120ANGLE (deg)

EDGECENTER

ENERGY (eV)

0

100

200

THE PROBLEM....

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•• The end result is a loss in CD control (center-to-edge) which, tollerable atlarger feature sizes is intolerable at smaller feature sizes.

50 nm

0.00

0.05

0.10

0.15

0.20

0.25

0.30

50 100 150 200 250 300FEATURE SIZE (nm)

EDGE

CENTERF

RA

CT

ION

AL

LOS

S IN

CD

SMART, AWARE AND PROACTIVE TOOLS

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• In spite of tremendous progress in the design of plasma tools, most suchtools are passive or, at best, reactive to their own environment.

• The case is made that continuing innovation requires Smart, Aware andProactive (SAP) tools.

• SMART: mentally alert, knowledgeable, shrewd

• AWARE: having or showing realization, perception or knowledge

• PROACTIVE: involving modification by a factor which proceeds that which is being modified.

Webster's New Collegiate Dictionary

• A SAP tool is one that:

• Senses its internal reactive environment• Has access to a knowledge base which enables it to interpret these

observations• Changes its environment to meet specifications.

THE CASE FOR SAP TOOLS

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• The move towards foundries by even major chip producers implies that alarger variety of processes will be performed in a given tool over itslifetime; and that those processes will change more frequently.

• Tools must be "reconfigurable" rapidly.• Tool memory effects may be unavoidable and unpredictable.

• As new materials are developed (e.g., low-k, high-k) having more stringentCDs, recipes will likely become more complex.

• What is optimum for one mixture is not optimum for another.• More demanding requirements to widen process windows.

• As wafer sizes and die complexity increase, the value/wafer enablesexpenditures which now are discounted.

DOES The KNOWLEDGE BASE EXIST FOR SAP TOOLS(OR CAN IT BE GENERATED?)

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• Realizing SAP tools requires an intimate knowledge of the cause-and-effect relationship.

"If I observe A and do B, then C will result."

• This cause-and-effect knowledge base can be generated by a range ofmethods ranging from empirical to a priori.

• Empirical: Conventional DOE• A priori: Predict from first principles• Semi-Empirical/A priori: First principles bounded or normalized

by empiricism.

• At present the knowledge base does not exist for SAP tools, largelybecause the observables A are too far removed from the outcomes C.

• The methodology and technologies to realize SAP tools do, however, existor can be developed.

GENERATION, APPLICATION AND EXTENSION OFKNOWLEDGE BASE: FEATURE EVOLUTION (D. B. Graves)

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• Advancing the knowledge base in feature evolution has required acombination of apriori, semi-empirical and empirical calculations andmeasurements, supported by validating experiments.

• The group/collaborators of D. B. Graves demonstrate this methodology.

• Sticking coefficients on evolvingsurfaces (CF3

+ on Si)• Reflection coefficients of ions

from surfaces (Cl2+ on Si)


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• Equipment Scale Modeling (IonEnergy Distributions)

• Feature Scale Modeling (Sietching by Cl2/HBr)


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• Validating data

• C.F. Abrams and D. B. Graves,JAP 86, 5938 (1999)

• M. Voyoda et al, JVSTB 18, 820(2000)

• B. Helmer and D. B. Graves,JVSTA 17, 2759 (1999)

ABC PRODUCT BUSINESS GROUPETCH PRODUCT BUSINESS GROUP

2

top grid (dc bias)

discriminator

collector

ion current I

repulsivevoltage V

+

0.1”

Examples of Plasma Diagnostic Tools Used inDevelopment of Etch Equipment

n Instrumented Wafers– Ion Current Flux– DC Bias– Ion Energy

Ion currentcollection disks

Ion currentcollection disks

WaferWafer

Ref: Peter K. Loewenhardt

ABC PRODUCT BUSINESS GROUPETCH PRODUCT BUSINESS GROUP

8

Position (in)

-4 -3 -2 -1 0 1 2 3 4

ICF

(m

A/c

m2 )

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Reference: ICF:European Semiconductor/Damage:P2ID

ICF ICF DamageDamage

2000W(4.6%)

1500W(3.8%)

1000W(3.4%)

500W(4.7%)

Cum

ulat

ive

Pro

babi

lity

1e-12 1e-11 1e-10

Leakage Current (Ig)

99

90

70

50

30

10

1

1800Watts

1000Watts

99

90

70

50

30

10

11e-12 1e-11 1e-10

Leakage Current (Ig)

Cum

ulat

ive

Pro

babi

lity

Source Power Window

Ref: Peter K. Loewenhardt

q A new diagnostic for detectingspecies and films formed on thereactor walls.

q What is formed on reactorwalls during etching? How doesit affect the plasma?

q Applications

Ø Detecting Fluorocarbonfilms on the walls

Ø SiOxCly films in Si etchingØ PECVD

Ø Monitoring reactor wallcleaning steps.

Ø Ref: Eray Aydil, UCSB,[email protected]

Multiple Total Internal Reflection Fourier Transform InfraredMultiple Total Internal Reflection Fourier Transform Infrared(MTIR-FTIR) surface probe(MTIR-FTIR) surface probe

From FTIRSpectrometer

To HgCdTe Detector

Chamber Wall

Internal Reflection Element

Plasma

In Situ Attenuated Total Reflection Fourier TransformInfrared (ATR-FTIR) Spectroscopy

RFQuartzWindow

Matching Network

HgCdTeDetector

Data AcquisitionGas Injection Ring

FTIR Spectrometer

KBr Windows

IR

ICP Source

RF bias

From IR Spectrometer To Detector


q During Cl2/O2 etching of Si, SiOxCly film deposits on the reactor walls.

q SiOxCly film must be etched from the reactor walls using F-containing plasma inbetween every wafer in a step referred to as Waferless Auto Clean (WAC).

q MTIR-FTIR probe help develop successful WAC in Lam’s TCP reactor for Si STIetching and improved productivity.

Incomplete Cleaning Step Optimized Cleaning Step

Application of MTIR-FTIR surface probe: reactor wall cleaningApplication of MTIR-FTIR surface probe: reactor wall cleaning


600 800 1000 1200 1400

0.0

0.2

0.4

0.6

0.8

1.0

1.2

After Cl 2/O2

etching of Si

Abs

orba

nce

Wavenumbers (cm-1)

After SF6/O2

plasma cleaning

600 800 1000 1200 1400

After Cl2/O2

etching of Si

Abs

orba

nce

Wavenumbers (cm -1)

After SF6/O2

plasma cleaning

0.0

0.2

0.4

0.6

0.8

MEMS (MICRO-ELECTRO-MECHANICAL SYSTEMS)MICROSENSORS FOR SMART WAFERS

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• The development of MEMS technologies provide the opportunity toimplement intra-tool sensors and, ultimately, on-wafer sensors resulting inthe wafer analogue of the smart-tool: the Smart Wafer

• MEMS sensors enable measurements of, for example, reactive fluxes to bemade at or near the wafer surface.

• Provides data directly relevant to process control

• Eliminates need to disengage complex relationships betweenmeasurements of, for example, OES and desired quantities such asflux.

• Smart Wafers may have unique sensors for individual processes, therebyeliminating the need for over-functionality to be built into the tool.

SUB-MICRON RETARDING FIELD ENERGY ANALYZER(M. BLAIN, Sandia National Labs)

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• Leveraging MEMS technologies, Blain et al have developed sub-micron ionenergy anlyzers which provide the means for non-perturbing, in-situ, on-wafer measurements.

• Micro-Ion Energy Analyzer fabricated using MEMS technologies

SUB-MICRON RETARDING FIELD ENERGY ANALYZER(M. BLAIN, Sandia National Labs)

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0 10 20 30 40 50

0.0

4.0x10-8

8.0x10-8

1.2x10-7

1.6x10-7100 sccm Ar

10 mT200 Ws

Energy (eV)

f(v)

Bias Power: 0 Wb

25 Wb

50 Wb

• Ion energydistributionsobtained on rf-biased substrate inICP-GECRC

• With multiplesensors acrosswafer, real-timeassessments ofquality anduniformity of ionfluxes are possible.

VIRTUAL PLASMA EQUIPMENT MODEL (VPEM)

MURI9920

UNIVERSITY OF ILLINOISOPTICAL AND DISCHARGE PHYSICS

l The Virtual Plasma Equipment Model (VPEM) is a “shell” which supplies sensors, controllers and actuators to the HPEM.

HPEM

CONTROLLERMODULE

INITIAL AND OPERATING CONDITIONS

SENSOR POINTS AND ACTUATORS

SENSORMODULE

ACTUATORMODULE

SENSOROPERATING

POINTS

“DISTURBANCE”

PID CONTROLLER

AVS9908


•• A Proportional-Integral-Differential (PID) controller has been implementedin the VPEM.

• Proportional:

( ) SignalErrorSSSSS

gAA o =−=∆∆

⋅⋅=∆ ,

• PID

odi

Adt

SSdt

SS

SS

gA +

∫

∆

+∆

+∆

⋅= ττ1

where:

oSSS ,,∆ Error, current value and setpoint of sensor

g Gain of Controller

oAAA ,,∆ Change, current value and setpoint of actuator

id ττ , Differential and integraltime constants

PROCESS VARYING WALL CONDITIONS

AVS00_13


• During a process recipe, deposition on reactor side walls (or changes inprocess conditions) results in changes in reactive-sticking coefficients,producing both intra-run and run-to-run variations in performance.

• Chamber cleans are, in large part, necessary to "reset" the reactor to"initial conditions".

• Particle formation concerns aside, the difficulty in using real-time-controlto compensate for evolving wall conditions is the uncertainty in correlatingobservables (e.g., OES, actinometry) with fluxes to wafer surface.

• SATs and SAWs eliminate this uncertainty, by directly measuring processrelevant parameters.

• Example: Cl →→ Cl2 sticking coefficient increasing during process.

Cl →→ Cl2 STICKING COEFFICIENT

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• During a process, the sticking coefficient on chamber walls increases from0.01 to 0.4 due to deposition of etch products.

STICKING COEF. INCREASES

PERTURBED

UNPERTURBED

UNPERTURBED

Cl DENSITY

Cl2 DENSITY

5 1017

6 1017

7 1017

8 1017

9 1017

0.0

0.2

0.4

0.6

0.8

1.0

40 60 80 100 120ITERATION

UNPERTURBED

PERTURBED

Cl > Cl2STICKING

COEF.

Cl S

TIC

KIN

G C

OE

FF

ICIE

NT

ION

FLU

EN

CE

(1/

s)

Cl, Cl2 Densites with/without Perturbation Ion Fluence, Sticking Coef.

• Cl densities decrease, Cl2 densities increases, resulting in a decrease inthe ion flux to the on-wafer sensor.

• Ar/Cl2 = 70/30, 20 mTorr, 500 W, 200 sccm

Cl →→ Cl2 STICKING COEFFICIENT: ION FLUENCE-POWER RTC

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• A simple proportional controller with a wafer-level ion flux sensor is used.The desired ion fluence, perturbed by the change in Cl sticking coefficient,is largely recouped.

5 1017

6 1017

7 1017

8 1017

9 1017

450

500

550

600

650

40 60 80 100 120ITERATION

ION

FLU

EN

CE

(1/

s)

ICP

PO

WE

R

POWER

PERTURBED

CONTROLLEDTARGET

START RTC

• Ar/Cl2 = 70/30, 20 mTorr, 500 W, 200 sccm

CHOICE OF SENSOR FOR TRANSIENTS: ACTINOMETRY

GECA9909


•• The proper choice of sensor is critical to controlling through transients.

• Sensors which are adequate for perturbations to the steady state may failduring a transient.

• Example: Impulsively change the coefficient for Cl →→ Cl2 on walls whilekeeping the input flow rate and pressure constant.

Cl

Cl,

Cl 2

DE

NS

ITY

(10

13 c

m-3

)

Cl2 Ar

Ar

(101

2 cm

-3)

Startup Transient

Quasi-steadystate

[ Cl WALL Cl2 ] x 4• Sensor:

Actinometry ofCl*: S = [Cl*]/[Ar**]

• The decrease inoutflow resultingfrom morerecombinationincreases the Ardensity.

• 10 mTorr, 120sccm, Cl2/Ar =95/5, 500 W

CHOICE OF SENSOR FOR TRANSIENTS: ACTINOMETRY

GECA9909


• As a result of the absolute increase in Ar density (and Ar* signal) resultingfrom the change in mole fractions, the actinometry signal decreasesrelative to the actual Cl density.

Cl DENSITY

ACTINOMETRY

Cl D

EN

SIT

Y (

1013

cm

-3)

AC

TIN

OM

ET

RY

[Cl*

/Ar*

*] • Transients whichchange the molefraction of thereference willcomplicate use ofactinometry.

SMART WAFER: ION FLUX AND UNIFORMITY

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• Intra-process seasoning of walls changing reactive sticking coefficientsproduces changes in both magnitudes and uniformity of fluxes.

• Smart wafer techniques will be applied to control against changes in ionflux and uniformity following a change in sticking coefficient for Cl →→ Cl2.

TIME (µs) [accelerated]

Cl DENSITY

Cl2 DENSITY

PERTURBED

Cl > Cl2 : 0.05 > 0.4

ION FLUX UNIFORMITY ION FLUX

MAGNITUDE

ICP POWER (MAGNITUDE)

MAGNETIC FIELD (UNIFORMITY)

• Ar/Cl2 = 50/50, 20 mTorr, 500 W, 200 sccm

ION SOURCE AND FLUXES

AVS00_17


• Due to the increase in Cl2 resulting from the increase in Cl →→ Cl2 on wallsion sources are confined closer to the coils.

• The ion flux decreases and becomes more edge high.

UNPERTURBED (LOW Cl2) PERTURBED (HIGH Cl2)ION SOURCE FLUX VECTORS

• Ar/Cl2 = 50/50, 20 mTorr, 500 W, 200 sccm

ION FLUENCE MAGNITUDE AND UNIFORMITY

AVS00_18


• The shift in ion source to larger radius increases the ion flux at largeradius thereby making uniformity more edge-high.

• Larger rates of attachment and higher wall losses decrease the ion flux.

• These trends will be corrected using ICP power and B-field as actuators.

0 100

1 1017

2 1017

3 1017

4 1017

5 1017

6 1017

7 1017

0 500 1000 1500 2000 2500

[Points are sensor readings]

UNPERTURBED

PERTURBED


-0.20

-0.15

-0.10

-0.05

0.00

0 500 1000 1500 2000 2500


UNPERTURBED

PERTURBED

UNIFORM


EDGE-HIGH

CENTER-HIGH

ION FLUENCE (1/s) UNIFORMITY

• Ar/Cl2 = 50/50, 20 mTorr, 500 W, 200 sccm

MAGNETIC FIELD AS AN ACTUATOR

AVS00_20


• By applying moderate solenoidalmagnetic fields (a few - 10s G), radialand axial components of the inductivelycoupled field are generated.

• This results in shifts in the powerdeposition, and can be used as anactuator for ion flux uniformity.

• Ar/Cl2 = 70/30, 20 mTorr, 500 W, 200 sccm

0 GAUSS POWER DEPOSITION

5 GAUSS

5 GAUSS POWER DEPOSITION

CONTROLLED ION FLUX MAGNITUDE AND UNIFORMITY

AVS00_19


• Using proportional controllers with moderately high gain (0.5), uniformityand ion flux are restored to their target values.

• The use of on-wafer sensors insures target values directly correlate withdesired reactant properties.

0 500 1000 1500 2000 2500


CONTROLLED

PERTURBED

TARGET


450

500

550

600

650

700

750

800

POWER

PO

WE

R (

W)

0

2

3

1

4

5

6

-0.20

-0.15

-0.10

-0.05

0.00

0 500 1000 1500 2000 2500

CONTROLLED

PERTURBED

UNIFORMEDGE-HIGH

CENTER-HIGH


0

4

8

12

[Points are sensorreadings]

B-FIELD

B-F

IELD

(G

auss

)

ION FLUENCE (1017/s) UNIFORMITY

• Ar/Cl2 = 50/50, 20 mTorr, 500 W, 200 sccm

TAPERING AND BOWING OF PROFILES

AVS00_23


• Feature profiles in fluorocarbon plasma etching of SiO2 often have bowedor tapered profiles.

SiO2

PR

BOWED TAPERED

C Cui (AMAT)

• Control of profile CD (and selectivity) ultimatelydepends on control of not only uniformity andmagnitude of reactants, but also flux composition.

• For example, bowing and tapering have beencorrelated with the ratio of polymerizing radicalfluxes to ion fluxes.

• On wafer measurements of species resolved,neutral and ion resolved fluxes are beyond the stateof the art.

• However, innovating such sensors may be the keyto maintaining CDs to 0.08 nm and beyond.

CORRELATION OF PROFILE WITH REACTANT FLUX RATIOS

AVS00_24


• Results from integrated plasma equipment and feature profile modelinghave shown that SiO2 feature profiles can be correlated with the ratio ofthe passivating neutral flux to the ion flux.

8.4 10.2 12

Photoresist

SiO2

Φn/Φion = 6

Wb

/ Wt

Dep

th (

µm)

Wb / Wt

Depth

Φn / Φion

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

0.0

0.5

1.0

1.5

2.0

2.5

3.0

7 8 9 10 11 12

ΦΦnΦΦ/ion : Passivating Neutral/Ion flux Wb/Wt: Bottom Width / Top Width

• Quantitative knowledge of these trends, coupled with measurement ofcomposition of reactive flux, provide the means ot control profile CD.

SMART WAFER: ION FLUX AND ION/NEUTRAL RATIO

AVS00_25


• Intra-process seasoning of walls changing reactive sticking coefficientsproduces changes in both magnitudes and ratio of fluxes.

• Smart wafer techniques will be used to control changes in ion flux andneutral/ion flux ratio following a change in sticking coefficient for CF2.

NEUTRAL POLYMERIZING FLUX


PO

LYM

ER

IZIN

G /

ION

FLU

X

POLYMER / ION FLUX

INCREASE IN CF2 STICKING COEF.

0

5

10

15

20

25

0 200 400 600 800 1000 1200

PO

LYM

ER

IZIN

G F

LUX

(10

17/c

m2 -

s)

0

0.5

1.0

1.5

2.0

2.5

PERTURBED

• An increase in CF2 stickingcoefficient on wallsdecreases thepolymerizing flux (mostlyCF2 and CF).

• The ion flux remains nearlyconstant, producing alarge decrease in theneutral/ion flux ratio.

• Ar/C2F6= 60/40, 15 mTorr, 500 W, 200 sccm

Ar/C2F6 ION FLUX AND NEUTRAL/ION RATIO vs PRESSURE

AVS00_26


• To determine process variables to control, computational (or experimental)DOEs are performed.

• Power (to control ion flux) and pressure (to control ineutral/ion flux ratio)are chosen.

ION FLUX

NEUTRAL FLUX

RATIO

FLU

X (

1016

/cm

2 -s)

NE

UT

RA

L / I

ON

FLU

X

0.0

0.5

1.0

1.5

2.0

2.5

0

1

2

3

4

5

0 10 20 30 40PRESSURE (mTorr)

ION FLUX MAGNITUDE

ICP POWER (ION FLUX)

GAS FLOW RATE- PRESSURE (RATIO)

NEUTRAL POLYMER FLUX MAGNITUDE

• Ar/C2F6= 60/40, 500 W, 200 sccm

Ar/C2F6 NEUTRAL/ION RATIO CONTROLLED

AVS00_27


• Using power and pressure as actuators, the on wafer flux sensors directincreases in both values to maintain flux ratios and power constant.

TIME (µs) [accelerated]P

RE

SS

UR

E (

mT

orr)

PRESSURE

NE

UT

RA

L / I

ON

FLU

X

RATIO

PERTURBED

UNPERTURBED

CONTROLLED

CONTROL

STICKING

0

4

8

12

16

20

0

10

20

30

40

50

0 200 400 600 800 1000 1200

TARGET

• With on wafersensors, profile CDcontrol is directlycorrelated tomeasurements.

• Ar/C2F6= 60/40, 200sccm

CONFLUENCE OF MICROELECTRONICS-AND-MEMS:SYSTEMS ON-A-CHIP

AVS00_06


• The plasma processing community has been slow to recognize andpotential of combining microelectronics with MEMS to create systems-on-a-chip.

• The ITRS lists examples of future SOCs, and cites cost as the presentlimiting factor in developing such systems.

Int. Tech. Roadmap Semi.: System-on-Chip 1999

• Never-the-less, market forces will drive this integration, and so theknowledge base to implement it should be addressed now.

[MEMS at DARPA 3.ppt] Slide 25Microsystems Technology Office

DARPADARPA

MTOMTO

Approved for Public Release - Distribution Unlimited

MEMS Actuators for Data StorageMEMS Actuators for Data Storage

Areal density: 1-100 Gb/cm2

Transfer Rates: 0.1-10 Mb/sSize: 0.5 cm3

Power consumption: <1W

Parallel atomic force imaging with MEMS to exceed densities of conventional magnetic and optical storage

[MEMS at DARPA 3.ppt] Slide 29Microsystems Technology Office

DARPADARPA

MTOMTO

Approved for Public Release - Distribution Unlimited

Advanced Digital Receiver (ATO)Advanced Digital Receiver (ATO)Digital IF w/ Bandpass Sampling

SiGe ASIC

C6x DSP

VCSELInterconnect

High SpeedADCs

FilterTo

Modem

Filter

DSP

RF MEMS

FilterFilterRF

Input

Frequency Synthesis

A/D

COMBINING ORGANIC LEDs WITH CMOS

AVS00_34


• Combining organic light-emitting-diodes with CMOS provides a means forSi-based optical interconnects for inter/intra-die communication.

8 x 8 OLED with CMOS Circuitry Laser Focus, September 2000, p.38

MEMS FABRICATION BRING NEW CHALLENGES

AVS00_35


• Although MEMS dimensions are now large by microelectronics standards,extreme aspect ratios push the state of the art. As MEMS dimensionsshrink, these HAR features will rapidly exceed the state-of-the-art.

J. MEMS 8, 403 (1999)

Accelerometer fabricated with Deep RIE

JVST B 18, 1890 (2000)

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• Extreme HAR etching using Cl2and SF6/O2 chemistries (l) 5 hr Cl2 ICP etch with (r) 10 min

widening process

A Microfabricated Inductively CoupledPlasma Generator

Jeffrey A. Hopwood

J MEMS9, 309 (2000)

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• Innovative SAP tools may use real-time-control with sensor equippedsmart wafers to guide arrays of plasma sources fabricated using MEMStechniques.

HUMAN RESOURCES: THE SOURCE OF INNOVATION

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• Ultimately, our ability to sustain innovation in our field relies on the talentof our human resources.

• Our field is perhaps unique is that innovations are generally produced bybroadly educated scientists and engineers, as opposed to narrowlydefined specialists.

• As a result, the "yield" from science and engineering college graduates istypically not high.

• To maintain and increase our progress, we must continue to capture thebest and brightest of our college graduates.


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0

250,000

500,000

750,000

1,000,000

1,250,000

0

2

4

6

8

10

1965 1970 1975 1980 1985 1990 1995 2000YEAR

% PHYSICAL SCIENCES

% ENGINEERING

ALL BS DEGREES

ALL

BS

DE

GR

EE

S

% P

HY

SIC

AL

SC

IEN

CE

AN

D E

NG

INE

ER

IG

0

100,000

200,000

300,000

400,000

500,000

0

5

10

15

1965 1970 1975 1980 1985 1990 1995 2000YEAR

% PHYSICAL SCIENCES

% ENGINEERING

ALL GRADUATE DEGREES

ALL

GR

AD

UA

TE

DE

GR

EE

S

% P

HY

SIC

AL

SC

IEN

CE

AN

D E

NG

INE

ER

IG

• Although the totalnumber of BS andgraduate degreescontinues toincrease, thefractions inEngineering andPhysical Sciencesare decreasing.

Ref: NSF00-3100 S&E Degrees 1966-97


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• Although a single field in a given industry cannot change reverse thesetrends, the health of our field requires pro-active measures on our parts.

• Mentoring programs• University collaborations• Internships• Scholarships and Fellowships• Grammar and secondary school outreach.

• Student attitudes towards science and engineering, particularly for under-represented groups, are typically unchangeable after junior high. Outreachprograms must also target these younger prospects.

GENERATING THE KNOWLEDGEBASE

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• Generating the knowledge base required tofulfill this challenge is as large a challenge asimplementing the solutions.

• Collaborations are clearly the most viableoption to achieve these goals.

• Looking ahead 10 years, one must also reflecton how well industry wide collaborations haveserved us during the past 10 years.

• SRC, Sematech, DARPA, NSF Initiatives haveall served in this capacity with varying degreesof success.

• The emphasis on pre-competitive,collaborative research (industry-university-national lab) has, however, declined of late. Areassessment of that strategy is necessary.

FOR MORE INFORMATION

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•• Copy of today's presentation:

http://uigelz.ece.uiuc.edu →→ "Presentations" link at top of page

• PS-TuM7 [next paper], R.L. Kinder, "Electron Transport and PowerDeposition in Magnetically Enhanced Inductively Coupled Plasmas"

• PS2-ThA4, D. Zhang, "Reaction Mechanisms and SiO2 Profile Evolution inFluorocarbon Plasmas: Bowing and Tapering"

• PS1+MS-WeA7, E.A. Edelberg, "Productivity Solutions for EliminatingWithin-Wafer and Wafer-to-Wafer Variability in a Silicon Etch Processthrough Plasma and Surface Diagnostics"

• PS2-ThM8, M.J. Sowa, "Electron Temperature and Ion EnergyMeasurements with A High-resolution, Sub-micron, Retarding FieldAnalyzer"

• PS2-TuA2, H. Singh, "Comprehensive Measurements of Neutral and IonNumber Densities, Neutral Temperature, and EEDF in a CF4 ICP"

sustaining another decade of innovation...

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