Precision Power Measurement Solutions from Bird
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- Slide 1
- Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird
- Slide 2
- Agenda National Standards Traceability- Challenges & Birds Solution RF Metrology Paths at Bird Electronic Corporation High power RF Calorimetry Low power microwave attenuation Low power microwave power MCS (master calibration system) Test Setups & system considerations 4020 Series Power Sensors and the 4421 Power Meter Typical Field Power Measurement Systems
- Slide 3
- National Standards Traceability- Challenges & Birds Solution
- Slide 4
- Generic Traceability Path National Reference Standard Measurement Reference Standard Working Standard NIST Bird Metrology Bird Manufacturing Facility Power Sensors
- Slide 5
- Power Measurement Requirements of the Semiconductor Industry Power Frequency Various frequency & power combos 13.56 Mhz 40 kW
- Slide 6
- Accuracy Capability of the Scientific Community Power Frequency Birds performance range & capability NIST, NPL etc.
- Slide 7
- Accuracy Capability of the Scientific Community Power Frequency Birds performance range & capability NIST, NPL etc. Calorimetry Path Precision Attn & Power Path
- Slide 8
- Birds Multi-Path Solution Primary Lab MCS Transfer Standard Working Standard Primary Standard NIST Attenation Standard NIST Fixed Attenuator Set Working Standard NIST Standard Working Standard Measurement Ref. Standard Test Setups NIST AC & DC Standard 4027, 40284024, 4025Model 43 Precision 60 Hz Power Analyzer High Power Calorimeter Low Power Precision Attenuator RF & Microwave Path Low Power RF & Microwave Power Path High Power RF Calorimetric Path Couplers + Power Meter VNAThermistor Mount Thermistor CN Mount Micro- Calorimeter < 10 mw Coupler Verification Cal Factor Verification < 10 mw AC Voltage & Current Stds. MCS Transfer Standard Test Setups 4027, 40284024, 4025Model 43
- Slide 9
- Calibration Subtleties of the Bird System +/- 1% calibration requirements dictate daily calibration +/- 3% is calibrated every 6 months +/- 5% is calibrated annually Cross correlations are on-going and constant Multiple paths are used to cross correlate high power & high frequency standards It is capital intensive, time consuming, and demands high skill levels, but worth every effort in order to guarantee the high accuracy demands of the semiconductor industry
- Slide 10
- RF Metrology Paths at Bird Electronic Corporation High power RF Calorimetry Low power microwave attenuation Low power microwave power MCS (master calibration system) Test Setups & system considerations
- Slide 11
- Primary Lab Working Standard Measurement Ref. Standard NIST AC & DC Standard Precision 60 Hz Power Analyzer High Power Calorimeter AC voltage & Current Stds. High Power RF Calorimetric Path Calorimetry is the critical link between high power AC standards & high power RF standards
- Slide 12
- 8860 6091 Power (kW) =.263 x flow rate (GPM) x T ( 0 C) Calorimetric Power Meters
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- Bird Metrology Manufacturing Facility Calorimeter Block Diagram
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- Characteristics of Calorimetric Power Meters Highly Accurate, Especially When Using 60Hz Substitution Technique Measures True Heating Power, Regardless of Harmonic Content or Modulation Characteristics of Signals Requires Careful Setup and Maintenance, Due to Coolant Characteristics Long Settling Time
- Slide 15
- Specific Heat of Water
- Slide 16
- Precision AC Power Meter RF Calorimeter RF Source 60 Hz AC Source Measure 60 Hz power into calorimeter w/AC Power meter Adjust calorimeter display to match AC power meter Accuracy of AC standard has now been transferred to calorimeter When RF is supplied to load, read calibrated watts from calorimeter display AC Substitution Method
- Slide 17
- AC Substitution Technique Use Low Distortion 60Hz Source Calibrate Calorimeter Using Precision 60Hz Power Meter (Accuracy = 2 C Allow 1 hour For Stabilization
- Slide 18
- Transfer of Accuracy from AC to RF frequency VSWR RFAC (60 Hz) Calorimetric load has virtually identical response at both AC & RF
- Slide 19
- Days Error Calorimetric Stability
- Slide 20
- MCS Transfer Standard NIST Attenuation Standard NIST Fixed Attenuator Set Working Standard VNA Coupler verification < 10 mw MCS Transfer Standard Low Power Precision Attenuator RF & Microwave Path Provides the important link between low power, high frequency attenuation values & high frequency coupling values
- Slide 21
- Working Standard Precision Coupler Transfers the accuracy of the VNA to the precision coupler when the coupling value is determined VNA
- Slide 22
- Attenuation Standards VNA Attenuation Kit Attenuation kit traceable to NIST
- Slide 23
- Working Standard Primary Standard NIST Standard Thermistor Mount Thermistor CN Mount Micro- Calorimeter < 10 mw Cal Factor verification Low Power RF & Microwave Power Path Provides the link between high frequency low power standards and high frequency power meters MCS Transfer Standard MCS Transfer Standard
- Slide 24
- Working Standard Thermal Power Meter CN Thermister Mount Cal factor of power meter is verified with reference to Thermister mount
- Slide 25
- MCS Transfer Standard MCS Transfer Standard MCS Transfer Standard Provides the combinational accuracy of calibrated high frequency power & coupling standards into a single calibrated device that can be used as a measurement standard in a high frequency, high power test setup
- Slide 26
- Directional Coupler - Thermal Power Meter MCS Standard
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- Characteristics of Directional Coupler- Thermal Power Meter Standards Wide Dynamic Range Useful Frequency Range Determined by Directional Coupler Complicated Error Budget Internal Reference Uncertainty Mismatch Uncertainty Calibration Factor Uncertainty Fundamental Accuracy Limited by Knowledge of Directional Coupler Attenuation, as well as Power Meter Error Sources. Mismatch Uncertainty is a Major Contributor to Total Uncertainty
- Slide 28
- Precision Power Measurement Test Setups Test Setups 4027, 4028Model 43 Test Setups 4027, 4028 4024, 4025 Model 43
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- These two measurements must agree within +/-.2% 4027A +/-1% Calibration System
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- Test Results 4027A
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- 5 kW RF Generator at 13.56 MHz Bird 4020AM Power Sensor Bird 4421 Power Meter RF Matching Network Plasma Etching Chamber Mismatches are present at each interconnection of system components Bird Oil load p1p1 p1p1 p1p1 p2p2 p2p2 p2p2 p2p2 A Typical Field Calibration Setup
- Slide 32
- p1p1 p2p2 p2Sp2S S p1p2Sp1p2S p2p1p2Sp2p1p2S p 2 +/- p 1 p 2 p 2 = p 2 Total reflected signal Mismatch Uncertainty
- Slide 33
- p 2 +/- p 1 p 2 p 2 = p 2 1 + p 2 1 p 2 1 + ( p 2 +/- p 1 p 2 p 2 ) 1 - ( p 2 +/- p 1 p 2 p 2 ) VSWR (apparent) = = 1 + p 2 +/- p 1 p 2 p 2 1 - p 2 -/+ p 1 p 2 p 2 Recognize that this expression can be approximated as the product of VSWR (apparent) = 1 + p 2 1 p 2 x 1 +/- p 1 p 2 p 2 1 -/+ p 1 p 2 p 2 = 1 +/- p 1 p 2 p 2 + p 2 +/- p 1 p 3 2 1 -/+ p 1 p 2 p 2 + p 2 +/- p 1 p 3 2 Then: VSWR (true) x 1 +/- p 1 p 2 p 2 1 -/+ p 1 p 2 p 2 ~ VSWR (apparent) Very small contribution Mismatch Uncertainty
- Slide 34
- VSWR (true) x 1 +/- p 1 p 2 p 2 1 -/+ p 1 p 2 p 2 ~ VSWR (apparent) The true VSWR is multiplied by an uncertainty factor which can only be controlled by carefully choosing the reflection coefficients (p 1 and p 2 ) at the source and test points 1 - p 1 p 2 p 2 1 + p 1 p 2 p 2 1 - p 1 p 2 p 2 1 + p 2 1 p 2 Lower limit of multiplier factor = Upper limit of multiplier factor = Lower uncertainty limit of measured VSWR = = F- F- = F+ 1 + p 2 1 p 2 Upper uncertainty limit of measured VSWR =F+ Mismatch Uncertainty
- Slide 35
- Where: P g = Reflection Coefficient of Source P l = Reflection Coefficient of Load P g and P l are FREQUENCY DEPENDENT QUANTITIES! Mu (%) = 100 [(1 P g P l ) 2 1] Mismatch Uncertainty
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- p1p1 p2p2 p2Sp2S S p1p2Sp1p2S p2p1p2Sp2p1p2S S(1 +/- p 1 p 2 ) Total transmitted signal +/- dB (ripple) = 20 log | 1- p 1 p 2 | Transmission Uncertainty
- Slide 38
- If data is taken at discrete points, then each individual reading carries an uncertainty of +/- x dB High point Low point Ripple averaged out flatness Measurement uncertainty Transmission Uncertainty
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- Example of Typical RF System Error Budget
- Slide 42
- Slide 43
- These two measurements must agree within +/-.2% 4027A +/-1% Calibration System
- Slide 44
- Effects of Harmonics on Power Measurement 4027 Power Sensor Detector Scheme is Very Sensitive to Harmonics in the Signal. 4027 is Calibrated with Signals Having Harmonics of Less than 60dBc. Signals with Harmonic Content Greater Than 60dBc will Cause Offsets in Power Readings Effects of Harmonics are Determined not Only by Diode Response, but Also by Directional Coupler Response Characteristics, as well as Phase Relationships of Harmonic.
- Slide 45
- Effects of Harmonics on Power Measurement Worst Case Errors
- Slide 46
- Effects of Modulation on Power Measurement Detector Scheme Used in 4027 is Sensitive to Amplitude Modulation of the Signal. Magnitude of Change in Power reading is Related to Power Level and Instrument Range. Approximate Error: At 10% of Full Scale: 5% AM Results in 2% Error At 90% of Full Scale: 5% AM Results in 8% Error
- Slide 47
- Additional Tips for Making Accurate Power Measurements Know the effects of the mismatches present in the system architecture on the power measurement uncertainty Avoid the use of multiple adapters or non-compensated (high VSWR) adapters between cables and components Perform a system error budget to quantify the effects of mismatches and component tolerances in the system Avoid the use of long interconnecting cables, as the ripple period will be more frequent as the length is increased for a given frequency Use coupler based measurement techniques when the load is unstable or poor in performance compared to the system line impedance Averaging techniques over wider frequency bands can be effective in minimizing the effect of mismatch uncertainties
- Slide 48
- 4020 Series Power Sensors and the 4421 Power Meter
- Slide 49
- 4421/4020 Series Power Meters Highly Accurate, Highly Repeatable Power Meter System Long Product History, Introduced in 1988 Has Become the Power Meter of Choice in Semiconductor Processing Applications Extremely Wide Dynamic Range
- Slide 50
- Designed for Service in Semiconductor Processing Applications 1% Accuracy at Calibration Points Several Models to Address Specific Semiconductor Power Levels and Frequencies Model Power Range Frequency VSWR Range Directivity Insertion Loss 4027A12M 300 mW to 1 kW 10-15 MHz 1.0 to 2.0 28 dB
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