MKS Confidential8/12/2004
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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.
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Agenda
• Overview of VI Probe Product Family
• Technology Overview
• Data Acquisition and Analysis
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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
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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
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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
Philip Schmitt / Mark Rousavy
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
LowPass FilterHalfband
DecimationProcess
CIC
I Magnitude
I Phase
CurrentSample
Cos(n) Sin(n)
I
Q
Fn
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
LowPass FilterHalfband
DecimationProcess
CIC
I Magnitude
I Phase
CurrentSample
Cos(n) Sin(n)
I
Q
F2
X
X
Cos(n) Sin(n)
DigitalFrequencySynthesizer
Cartesianto
Polar
LowPass FilterHalfband
DecimationProcess
CIC
V Magnitude
V Phase
Frequency
I
Q
VoltageSample
X
X
Cartesianto
Polar
LowPass FilterHalfband
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?
Philip Schmitt / Mark Rousavy
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