Film Thickness Measurement Julian Peters Joe Fitzmyer Brad Demers P06402

Film Thickness MeasurementFilm Thickness Measurement

Julian Peters

Joe Fitzmyer

Brad Demers

P06402

AgendaAgenda

Project Overview & Background Needs, Requirements, and Specifications Concept Development Interferometry Background System Operation Analysis Bill of Materials Anticipated Design Challenges Senior Design II

Project Overview - Project Overview - BackgroundBackground

Meniscus Experiment in RIT Thermal Analysis Lab

Figure 1: Moving Meniscus Experiment Figure 2: Heater surface and water nozzle detail


Meniscus Experiment in RIT Thermal Analysis Lab

Figure 3: Operation of experiment

Heated, rotating copper cylinder

Meniscus

Evaporation

Direction of Rotation


Meniscus Experiment in RIT Thermal Analysis Lab – Unanswered Questions:– Is there a film of adsorbed water left behind the

moving meniscus?– How far does it extend?– What is its thickness?

Project Overview – Sponsor’s Project Overview – Sponsor’s Major NeedsMajor Needs

Ability to determine existence and thickness of film

Cost-effectivenessAbility to operate in a “dirty” environmentAccuracy, but not as demanding as

semiconductor applications

Key RequirementsKey Requirements

Must differentiate between film and no filmAbility to determine thickness profile of

film greatly desirableMust be able to take measurement quicklyMust not require constant input from user

Specifications & TargetsSpecifications & Targets

Positioning Accuracy – ± 0.25°Positioning Precision – ± 0.25°Film Thickness Accuracy – ± 5 μmFilm Thickness Precision – ± 5 μmMeasurement Time – 30 minutes

Concept DevelopmentConcept Development

Technologies Considered:– Physical Measurement

Thermal Cycle Testing Profilometry

– Acoustic Measurement Acoustic Reflections (e.g. ultrasound)

– Optical Measurement Ellipsometry Interferometry


Eliminating Concepts:– Physical Measurement

Lack of accuracy Will disturb film More sensitive to surface irregularities

– Acoustic Measurement Accuracy is a concern Implementation is not clear


Evaluate each additional concept against the baseline, score each attribute as: 1 = much worse than baseline concept 2 =

worse than baseline 3 = same as baseline 4 = better than baseline 5= much better

than baseline

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Price 3.0 4 1 21% 0.64 0.86 0.21

Accuracy 3.0 4 4 25% 0.75 1.00 1.00

space requirement 3.0 3 4 18% 0.54 0.54 0.71

speed 3.0 3 4 4% 0.11 0.11 0.14

adjustability/additional applications 3.0 2 3 0% 0.00 0.00 0.00

noise sensitivity 3.0 2 3 7% 0.21 0.14 0.21

range of measurements 3.0 2 3 14% 0.43 0.29 0.43

ease of use 3.0 4 3 11% 0.32 0.43 0.32

Additional 1 (Future Use) 0% 0.00 0.00 0.00

Additional 2 (Future Use) 0% 0.00 0.00 0.00

Weighted Score 3.0 3.4 3.0 3.0 3.4 3.0

Normalized Score 89.4% 100.0% 90.4%

Differentiation Among Optical Methods

Figure 4: Decision Matrix

i

Film Surface

Substrate Surface

1) Light is emitted from the laser diode.

2) Two reflections take place: part of the beam reflects from the film surface, part of it continues through the film and reflects from the substrate surface.

3)The two reflected beams recombine. The difference in the path length taken by the two beams manifests itself as a phase difference, which can cause attenuation of the beam intensity.

4) The recombined beam is collected at a sensor. The intensity is measured, and can be compared to the intensity of the original beam.

Interferometry in a NutshellInterferometry in a Nutshell

Figure 5: Interferometry Basics

System OperationSystem Operation

User initializes the measurement through a simple GUI

Stepper motors position goniometers at a range of angle increments

Photodiode captures a portion of light energy emitted at each angle increment

LabView controller inputs position data to stepper motors

LabView plots captured data and outputs measured thickness as well as error or confidence level of the measurement

Block DiagramBlock Diagram

Figure 6: Information and control flow through system

PC

Control Hardware Goniometer Stepper Motors

Laser Diode Power

PhotosensorLabView Data Collection Hardware

Operator

Light reflected from surface

Information

Control

Motors Goniometers

Laser diode

Photodiode

Anticipated System Operation

Figure 7: Assembly at 55° incident angle



Analysis of DesignAnalysis of Design

MATLAB code written to simulate reflectance response

Data from numerical experiments– Determine appropriate wavelengths– Analyze experimental data

Most easily identified parameter of data is the frequency of oscillations

Sample MATLAB ResultsSample MATLAB Results

0 10 20 30 40 50 60 70 80 900.5

0.55

0.6

0.65

0.7

0.75

0.8

0.85

0.9

0.95

1

Angle of Incidence, degrees

Rel

ativ

e in

tens

ity

=635 nm, s-polarization

film thickness=1 m

film thickness=10 m

film thickness=50 m

Figure 10: Oscillatory Reflectance Response

Sample MATLAB ResultsSample MATLAB Results

0 10 20 30 40 50 60 70 80 900.5

0.55

0.6

0.65

0.7

0.75

0.8

0.85

0.9

0.95

1


Rel

ativ

e in

tens

ity


film thickness=0 m

Figure 11: Non-Oscillatory Reflectance Response at Zero Film Thickness

MATLAB Code VerificationMATLAB Code Verification

0 10 20 30 40 50 60 70 80 900.7

0.75

0.8

0.85

0.9

0.95

1

Angle of Incidence (deg)

Rs

Rs for 10 micron layer, 633 nm light

WVASE

MATLAB

Figure 12: Comparison of WVASE32 and MATLAB Results

Off-the-Shelf ComponentsOff-the-Shelf Components•Laser diode: TIM-206 •Goniometers: GNL18/M-Z6

•Photodiode: S2684-650 •Motor Controller: DCX-PCI100

Bill of MaterialsBill of Materials

Figure 13: Anticipated Costs

Item # Part Description Purpose Company Part Number Price Qty needed Total Cost

1 Laser Diode650 nm laser

diode with 10mW output power

Emits beam focused on one

spot.Laser Dreams TIM-206 60.00$ 1 $60.00

2 Photodiode

High Sensitive Monochromatic

Silicon Pin diode. Sensitive to 650

nm light with interference filter

Measures power of reflected beam. Outputs measured

voltage.

Hamamatsu S2684-650 108.60$ 1 $108.60

3 Goniometer

Large Metric Mount with focus

1.75" away. 200

rotation in either

direction in 10

increments

Positions laser and sensor at a range of angles, with same focal

point and distance.

Thorlabs GNL18/M-Z6 450.00$ 2 $900.00

4 Laser Mount laser diode mount

Mounts laser diode to the

goniometer such that the laser

module does not extend past the

focal point

06402 Team Fabrication none -$ 1 $0.00

5 Sensor Mount photodiode mount

Mounts photodiode to the goniometer such

that the diode module does not extend past the

focal point


6 Goniometer Mount Position mount

Mounts goniometer with high positional

accuracy. Will be built to table.


7 PCI cardMotorized

controller card

Understands user inputs and relays them to motor.

Accurately postions and

synchronizes both motors. Reports data back to user

Thorlabs DCX-PCI100 1,195.00$ 1 $1,195.00

8 Multifunction DAQ 12-bit resolution

relays position and power

information to the operator

National Instruments NI-USB-6009 125.00$ 1 $125.00

$2,388.60$2,591.63

Bill of Materials and Cost

Total -->Total with Tax -->

Anticipated Design Anticipated Design ChallengesChallenges

Light Source– Beam divergence– Suitability of wavelength to film thickness– Consistency of intensity

Photodiode– Must accommodate beam divergence– Ability to differentiate changes in intensity of

the beam from random noise


Positioning Equipment– Accuracy– Repeatability– Synchronicity

Equipment Mounts– Must be accurately machined to avoid loss of

overall accuracy of system


PC Interface Hardware– Interface with positioning equipment must provide

program with position information– Must preserve the accuracy of the rest of the system

Data Interpretation Programming– Must be able to “fit” experimental data to simulated

data as accurately as possible– Some measure of confidence of fit would be useful to

user


Specific Application to Mensicus Experiment– Varying optical properties of surface due to

discoloration, physical imperfections, etc.– Misalignment of beam due to surface

imperfections– Alignment of rotating copper surface

Senior Design II PlanSenior Design II Plan

Order & fabricate partsAssemble functional setup as soon as

possibleTest setup against known films produced by

the RIT Microelectronic Engineering Dept.Develop code throughout quarterModify and revise design as needed and as

problems are encountered

Senior Design II PlanSenior Design II Plan

Order & fabricate partsAssemble functional setup as soon as

possibleTest setup against known films produced by

the RIT Microelectronic Engineering Dept.Develop code throughout quarterModify and revise design as needed and as

problems are encountered

Senior Design II ScheduleSenior Design II Schedule

Week 3 Week 4

Test System

Receive Ordered PartsMachine Team-Manufactured Parts

Write Control and DAQ CodeAssemble System

Week 9 Week 10

Week 5

Week 6 Week 7 Week 8

Week 1 Week 2

Write Reports, etc.

Write Control and DAQ CodeAssemble System

Test SystemRun Meniscus Tests

Figure 14: Senior Design II Gantt Chart

Any Questions?Any Questions?

Interferometry AnalysisInterferometry Analysis

for s-polarization

for p-polarization

for s-polarization

for p-polarization

0 10 20 30 40 50 60 70 80 900

0.2

0.4

0.6

0.8

1

1.2

1.4


Rel

ativ

e in

tens

ity


film thickness=1 m

film thickness=10 m

film thickness=25 m

0 10 20 30 40 50 60 70 80 900

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1


Rel

ativ

e in

tens

ity


film thickness=1 m

film thickness=10 m

film thickness=25 m

0 10 20 30 40 50 60 70 80 900.5

0.55

0.6

0.65

0.7

0.75

0.8

0.85

0.9

0.95

1


Rel

ativ

e in

tens

ity


film thickness=25 m

film thickness=50 m

film thickness=100 m

0 10 20 30 40 50 60 70 80 900.75

0.8

0.85

0.9

0.95

1


Rel

ativ

e in

tens

ity


film thickness=1 m

film thickness=10 m

film thickness=25 m

0 10 20 30 40 50 60 70 80 90

0.4

0.5

0.6

0.7

0.8

0.9

1


Rs


WVASE

MATLAB

0 10 20 30 40 50 60 70 80 900.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Angle of Incidence

Rp

Rp for 1 micron layer, 400 nm light

WVASE

MATLAB

0 10 20 30 40 50 60 70 80 900.5

0.55

0.6

0.65

0.7

0.75

0.8

0.85

0.9

0.95

1


Rp


WVASE

MATLAB

0 10 20 30 40 50 60 70 80 900

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

Angle of Incidence (Degrees)

Rp

Rp for 10 micron layer, 400nm light

WVASE

MATLAB

0 10 20 30 40 50 60 70 80 900.4

0.5

0.6

0.7

0.8

0.9

1

Angle of Incidence

Rp


WVASE

MATLAB

0 10 20 30 40 50 60 70 80 900

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1


Rp


WVASE

MATLAB

0 10 20 30 40 50 60 70 80 900.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1


Rp


WVASE

MATLAB

0 10 20 30 40 50 60 70 80 900

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1


Rs


WVASE

MATLAB

0 10 20 30 40 50 60 70 80 900.86

0.88

0.9

0.92

0.94

0.96

0.98

1

Angle of Incidence

Rs


WVASE

MATLAB

0 10 20 30 40 50 60 70 80 900

0.2

0.4

0.6

0.8

1

1.2

1.4

Angle of Incidence

Rs


WVASE

MATLAB

0 10 20 30 40 50 60 70 80 900.7

0.75

0.8

0.85

0.9

0.95

1


Rs


WVASE

MATLAB

0 10 20 30 40 50 60 70 80 900

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1


Rs


WVASE

MATLAB

Documents

Film Thickness Measurement Julian Peters Joe Fitzmyer Brad Demers P06402