rf metrology - tools and process capability€¦ · rf metrology - tools and process capability...

MKS Confidential8/12/2004

1

RF Metrology - Tools and Process Capability

Philip Schmitt / Mark Rousavy

8/9/04

This presentation will provide technical capabilities of the MKS V/I Probe family of RF metrology tools and discuss the data collection capabilities of the MKS Toolweb Blue Box. The discussion will also touch on using multivariate analysis tools on process data for fault detection.


2

Agenda

• Overview of VI Probe Product Family

• Technology Overview

• Data Acquisition and Analysis


3

V/I Probe® RF Impedance Analyzer

Non-intrusive, independent, real time, accurate measurement of load V, I and phase angle

which monitors multiple frequencies at the same time

Real-time assessment of RF subsystem healthand

Ability to characterize key process applications to maintain and enhance

process uniformity, control and consistency


4

V/I Probe® Impedance AnalyzerMeasurement Parameters

• Basic Measurement Parameters– RMS Voltage– RMS Current– Phase relationship between Voltage & Current– Frequency

• Derived Measurement Parameters• Impedance (Z) • Load Power(VICos[Ø])• Forward/Reflected Power • Reactive Power (VISin[Ø])• Γ (Reflection Coefficient) • SWR and others

VIφ cos

Phase & Magnitude Extraction

V wave

I wave Delivered Power (V x I x Cos φ)DSP Algorithm for Delivered Power Calculation


5

V/I Probe® Impedance AnalyzerBlock Diagram and Installation

RF GeneratorMatching Network

Analysis Board

Plasma Chamber

Probe

Host RS-232

Interface

Fiber

Optic

Standard Configuration

RF Generator

Plasma ChamberHost RS-232

Interface

Fiber

Optic

Optional Integrated

Configuration

ProbeMatching Network

Combined DSP-based MW & Probe

Analysis Board


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Overview of VI Probe Product Family

• 2 Types of VI Probes:• Scanning – Monitors 1 frequency at a time over a

user specified range• Broadband – Monitors and tracks 2 fundamental

frequencies and up to 5 harmonic frequencies for each fundamental (12 frequencies total) simultaneously


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Typical Uses

• Scanning VI Probe:– Ideal for the single frequency applications (fixed frequency)– Capable of measuring Harmonics on higher power processes using

sequential measurements

• Broadband VI Probe:– Ideal for multiple frequency chambers or processes– Enables tracking of up to 2 Fundamental frequencies– Enables real time simultaneous data collection of all monitored frequencies– Improved signal to noise performance on harmonics

• Harmonic data used for end point detection, process and chamber finger printing, process and chamber SPC


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Performance ComparisonVI Probe

350VI Probe

4100VI Probe

Broadband

RF

Frequency range 325kHz to 50MHz 600kHz to 100MHz 400kHz to 150MHz

Frequency Monitoring 1 frequency at a time 1 frequency at a time2 fundamental simultaneouslyLower Frequency Range: <16MHzUpper Frequency Range: >16MHz

Harmonic Monitoring 5 Harmonics for each fundamental

RFFu

ndam

enta

l

Voltage Repeatability +/- 1% +/- 1% +/- 1% Current Repeatability +/- 1% +/- 1% +/- 1%Power Accuracy(50 ohms) +/- 1% +/- 1% +/- 1%

Phase Accuracy +/- 0.7 degrees +/- 0.7 degrees +/- 0.7 degrees

Impedance Accuracy +/- 1.5% +/- 1.5% +/- 1.5%

Voltage Minimum(Meet Accuracy)

TBD TBD 1.0 V

Current Minimum(Meet Accuracy)

TBD TBD 75 mA

Voltage Dynamic Range(Full Scale, Meet Accuracy)

~60 dB ~60 dB 70 dB

Current Dynamic Range(Full Scale, Meet Accuracy))

~60 dB ~60 dB 60 dB

Frequency Accuracy 100 PPM 100 PPM 100 PPMPhase Sensitivity +/- 0.7 degrees +/- 0.7 degrees +/- 0.7 degrees

Fund

amen

tal


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Performance Comparison (con’t)VI Probe

350VI Probe

4100VI Probe

Broadband

Harm

onic

s

Voltage Repeatability +/- 1% +/- 1% 1.00%Current Repeatability +/- 1% +/- 1% 1.00%Phase Accuracy +/- 0.7 degrees +/- 0.7 degrees +/- 1.0 degreesImpedance Accuracy 1.50% 1.50% +/- 2.0%Voltage Dynamic Range ~ 60 dB ~ 60 dB >70 dBCurrent Dynamic Range ~ 60 dB ~ 60 dB > 60 dBPhase Sensitivity +/- 0.7 degrees +/- 0.7 degrees +/- 0.7 degrees

Elec

trica

lHa

rmon

ics

Phase Range +/- 180 degrees +/- 180 degrees +/- 180 degreesVoltage Range(Working / Max)

2500 Vrms10 kVrms

2500 Vrms10 kVrms

4500 V rms10 kV rms

Current Range(Working / Max)

110 A rms135 A rms

110 A rms135 A rms

110 A rms135 A rms

Communication RS-232 RS-232 RS-232, EthernetNote: Impedance accuracy for up to 90:1 VSWR Load (other loads possible, but may affect accuracy)

Elec

trica

l


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How Does It Work? The Basics


8/9/04


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Frequency Scanning System• Utilizes a baseband mixing approach for processing of the RF

sensor signals.

X

X

DSP and SupportingHardware

24-bitA/D

Converter

J2 - Voltage Channel

J1 - Current Channel

Local OscillatorSerial Program Interface

3

4

A/D ConverterSerial Interface

A/D ConverterReset Line

Local OscillatorCircuit

Serial Interface(Fiber/Wire)

2

RF Input(0 - 10Vp-p)

Ethernet Interface

24

Low Pass

Filter

Low Pass

Filter

RF Input(0 - 10Vp-p)


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Scanning Spectrum

0

0.2

0.4

0.6

0.8

1

1.2

0 20000000 40000000 60000000 80000000 100000000 120000000 140000000 160000000

Frequency

Valu

e

Series1


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Scanning Spectrum

0

0.2

0.4

0.6

0.8

1

1.2

0 20000000 40000000 60000000 80000000 100000000 120000000 140000000 160000000

Frequency

Valu

e

Series1


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Scanning Spectrum

0

0.2

0.4

0.6

0.8

1

1.2

0 20000000 40000000 60000000 80000000 100000000 120000000 140000000 160000000

Frequency

Valu

e

Series1


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Scanning Spectrum

0

0.2

0.4

0.6

0.8

1

1.2

0 20000000 40000000 60000000 80000000 100000000 120000000 140000000 160000000

Frequency

Valu

e

Series1


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Scanning Spectrum

0

0.2

0.4

0.6

0.8

1

1.2

0 20000000 40000000 60000000 80000000 100000000 120000000 140000000 160000000

Frequency

Valu

e

Series1


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Scanning Spectrum

0

0.2

0.4

0.6

0.8

1

1.2

0 20000000 40000000 60000000 80000000 100000000 120000000 140000000 160000000

Frequency

Valu

e

Series1


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Scanning Spectrum

0

0.2

0.4

0.6

0.8

1

1.2

0 20000000 40000000 60000000 80000000 100000000 120000000 140000000 160000000

Frequency

Valu

e

Series1


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Scanning Spectrum

0

0.2

0.4

0.6

0.8

1

1.2

0 20000000 40000000 60000000 80000000 100000000 120000000 140000000 160000000

Frequency

Valu

e

Series1


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Scanning Spectrum

0

0.2

0.4

0.6

0.8

1

1.2

0 20000000 40000000 60000000 80000000 100000000 120000000 140000000 160000000

Frequency

Valu

e

Series1


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Problems of the Frequency Scanning

• Frequency tracking

• Sequential frequency processing– Slow data rate

• Poor SNR at harmonic


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Broadband System Design Objectives

• Concurrently monitor multiple RF frequencies

• Autonomously track RF fundamental frequency(s) for frequency tuning systems transient detection and plasma instability

• Wider Bandwidth: 150 MHz

• Optimized front end attenuation for two fundamental frequencies

• Improved Harmonic signature analysis

• Improved sampling and data rate


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Functional Diagram

Broadband Probe System

A/DConverter

PairFPGA

VHF

IHF

DSP

CurrentSample

VoltageSample

A/DConverter

PairFPGA

VLF

ILF

CurrentSample

VoltageSample

LowPassFilter

LowPassFilter

HighPassFilter

HighPassFilter

RF VoltageInput

RF CurrentInput


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Signal Processing Architecture

Broadband Probe System

X

X

Cos(n) Sin(n)

DigitalFrequencySynthesizer

Cartesianto

Polar

LowPass FilterHalfband

DecimationProcess

CIC

V Magnitude

V Phase

FrequencyDiscriminator

&Low Pass

Filter

Frequency

I

Q

VoltageSample

X

X

Cartesianto

Polar


DecimationProcess

CIC

I Magnitude

I Phase

CurrentSample

Cos(n) Sin(n)

I

Q

Fn

X

X

Cos(n) Sin(n)


Cartesianto

Polar


DecimationProcess

CIC

V Magnitude

V Phase

FrequencyDiscriminator

&Low Pass

Filter

Frequency

I

Q

VoltageSample

X

X

Cartesianto

Polar


DecimationProcess

CIC

I Magnitude

I Phase

CurrentSample

Cos(n) Sin(n)

I

Q

F2

X

X

Cos(n) Sin(n)


Cartesianto

Polar


DecimationProcess

CIC

V Magnitude

V Phase

Frequency

I

Q

VoltageSample

X

X

Cartesianto

Polar


DecimationProcess

CIC

I Magnitude

I Phase

CurrentSample

Cos(n) Sin(n)

I

Q

F1

FPGA

DSP

1600MOPSperfrequency

1.28 TOPS in total


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BB Spectrum Channel 1 (<16 MHz)

0

0.2

0.4

0.6

0.8

1

1.2

0 2000000 4000000 6000000 8000000 10000000 12000000 14000000 16000000 18000000

Frequency

Valu

e

Series1

Digital Filters

Analog Low Pass Input Filter BW

•Analog filter corner is dependent upon application


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BB Spectrum Channel 2 (>16 MHz)

0

0.2

0.4

0.6

0.8

1

1.2

0 10000000 20000000 30000000 40000000 50000000 60000000

Frequency

Valu

e

Series1

Spectrally Folded Frequencies

Digital Filters

Analog High PassInput Filter BW

•Analog filter corner is dependent upon application


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• Frequency tracking is accomplished by taking the derivative of the phase with respect to time.

• As the frequency varies, the frequency synthesizer is adjusted to maintain the position of the frequency in the digital filter’s frequency response.

Key Features: Frequency Tracking


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Frequency Tracking Active Load

• Dual Frequency tracking while RF sources are programmed to sweep.• Performed while significant plasma transients (arcs) were occurring.

Frequency trackers never lose lock.


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Other Key Features• Scaleable Architecture

– System delivered based on customer’s specified features.– FPGA and DSP field upgrades to add customer features.

• Simultaneous operation of multiple communication ports.

• High speed sampling and data rate


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Applications

• The VI Probe is– Sensitive to tool health– Sensitive to process

• Chamber Characterization– Fingerprinting v. SPC– Arc detection

• Advanced Process Control– Endpoint– Plasma uniformity– Impedance measurement for RF pulsing applications– Fast sampling for plasma diagnostics– Plasma closed loop control


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Great Instrument! , But What do we do with

the Data?


8/9/04


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The Issue

• Modern APC strategies require that integrated RF metrology data be correlated in real time, with internal tool data and with Recipe, Lot-ID and Wafer number

• However, most process tools support only a single SECS or HSMS connection- typically occupied by the factory host.

How to correlate RF metrology in real time with tool data to optimize the process?


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TOOLweb™ BlueBox Solution

• The optimum solution for data sharing.

• Multiplexes the data from the process tool and sensors such as a VI Probe

• Communicates this data to the multiple applications and users, including the factory host.

• Open, flexible architecture guarantees easy integration into existing fabenvironments


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Data Flow Through Blue Box

SECS HostSECS Host SECS MUX

Tool Side Interface

Fab Side Inteface

TOOLweb FabSide Protocol

TOOLweb ToolSide Protocol

SECS/GEM Tool Interface

SECS/GEM Host Interface

DataCollection

SECS HostSECS Host SECS MUX

Tool Side Interface

Fab Side Inteface

TOOLweb FabSide Protocol

TOOLweb ToolSide Protocol

SECS/GEM Tool Interface

SECS/GEM Host Interface

DataCollection


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Charts and Results

• Data from the Blue Box can be viewed in real-time or exported- including VI Probe data

• Data from VI Probe is viewed and analyzed offline

• Multivariate analysis is shown using VI Probe data in combination with tool sensor data.


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Example of Real-time data streamed into the Blue Box.

• Real-time selection of sensor(s) to view

• View variable by ID number or name

• Export raw data into several formats directly from Blue Box

Real-time Data on Blue Box


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Example: VI Probe Data

Deviation in Forward and Reverse Power at Sample 2800

Forward Power is off at Sample 8200


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VI Probe Data

Deviation in V and I data captured again at Sample 2800

V and I data is captured when Forward power = 0 at Sample 8200


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VI Probe Data

Deviation in Phase data captured again at Sample 2800

Phase data is also captured when Forward power = 0 at Sample 8200


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Combining VI Probe and Tool Data

• Blue Box collects data for applications such as TOOLwebServer and Simca-P+.

• Simca-P+ models use data obtained from the VI Probe and process tool.

• Once Simca-P+ models are created they can be run directly on the TOOLweb Server in real-time as the data is being streamed from the Blue Box


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MVA of VI Probe & Tool Data

VI probe signals reveal that the outlier wafer 64 is due to RF turn off.

VI probe shows that wafers 22 and 31 are different from the others

Score Plot

2231

64

VI Probe Variable Plot

Contribution Plot

Outlier Wafer 64

Alarm limit VI signal low

RF low

VI Probe and SVID data


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Drill Down: VI Probe Signals

22

31 •64

VI Probe data example from CVD process

Wafer 64 is identified as an outlier on T2 plot


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Conclusion

• Combined data from VI Probe and process tool: – Increases accurate fault detection in a process– Enables problem identification associated with specific

wafers using multivariate analysis

rf metrology - tools and process capability€¦ · rf metrology - tools and process capability...

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