Precision Power Measurement Solutions from Bird Precision Power Measurement Solutions from Bird

Agenda National Standards Traceability- Challenges & Bird’s 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

National Standards Traceability- Challenges & Bird’s Solution

Generic Traceability Path National Reference Standard Measurement Reference Standard Working Standard NIST Bird Metrology Bird Manufacturing Facility Power Sensors

Power Measurement Requirements of the Semiconductor Industry Power Frequency Various frequency & power combos Mhz 40 kW

Accuracy Capability of the Scientific Community Power Frequency Bird’s performance range & capability NIST, NPL etc.

Accuracy Capability of the Scientific Community Power Frequency Bird’s performance range & capability NIST, NPL etc. Calorimetry Path Precision Attn & Power Path

Bird’s 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, , 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, , 4025Model 43

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

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

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

Power (kW) =.263 x flow rate (GPM) x  T ( 0 C) Calorimetric Power Meters

Bird Metrology Manufacturing Facility Calorimeter Block Diagram

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

Specific Heat of Water

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

AC Substitution Technique Use Low Distortion 60Hz Source Calibrate Calorimeter Using Precision 60Hz Power Meter (Accuracy = <0.1%) Apply Unknown RF Source to Calorimeter Adjust Coolant Flow Rate to Maintain ΔT Across Load of > 2º C Allow 1 hour For Stabilization

Transfer of Accuracy from AC to RF frequency VSWR RFAC (60 Hz) Calorimetric load has virtually identical response at both AC & RF

Days Error Calorimetric Stability

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

Working Standard Precision Coupler Transfers the accuracy of the VNA to the precision coupler when the coupling value is determined VNA

Attenuation Standards VNA Attenuation Kit Attenuation kit traceable to NIST

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

Working Standard Thermal Power Meter CN Thermister Mount Cal factor of power meter is verified with reference to Thermister mount

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

Directional Coupler - Thermal Power Meter MCS Standard

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

Precision Power Measurement Test Setups Test Setups 4027, 4028Model 43 Test Setups 4027, , 4025 Model 43

These two measurements must agree within +/-.2% 4027A +/-1% Calibration System

Test Results 4027A

5 kW RF Generator at 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

p1p1 p2p2 p2Sp2S S p1p2Sp1p2S p2p1p2Sp2p1p2S p 2 +/- p 1 p 2 p 2 = p 2 ’ Total reflected signal Mismatch Uncertainty

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 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 /+ 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

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 p 1 p 2 p p 1 p 2 p 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

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

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

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

Example of Typical RF System Error Budget

These two measurements must agree within +/-.2% 4027A +/-1% Calibration System

Effects of Harmonics on Power Measurement 4027 Power Sensor Detector Scheme is Very Sensitive to Harmonics in the Signal 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.

Effects of Harmonics on Power Measurement Worst Case Errors

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

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

4020 Series Power Sensors and the 4421 Power Meter

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

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 MHz 1.0 to dB <0.05 dB 4027A250K 3 W to 10 kW kHz 1.0 to dB <0.05 dB 4027A400K 3 W to 10 kW kHz 1.0 to dB <0.05 dB 4027A800K 3 W to 10 kW kHz 1.0 to dB <0.05 dB 4027A2M 3 W to 10 kW MHz 1.0 to dB <0.05 dB 4027A4M 3 W to 10 kW 3-5 MHz 1.0 to dB <0.05 dB 4027A10M 3 W to 10 kW MHz 1.0 to dB <0.05 dB 4027A25M 3 W to 10 kW MHz 1.0 to dB <0.05 dB 4027A35M 3W to 10 kW MHz 1.0 to dB <0.05 dB 4027A60M3W to 6kW45-65 MHz1.0 to 2.028dB<0.05 dB ± 4027A Precision Power Sensor

First generation diode detectors operate over transition region of diode response curve limiting use in modulated communications systems. The entire dynamic range of the 4027 series sensor is contained within the square law operating range of the detector Sensor will behave similar to a thermal device, responding to the heating power of the signal being measured = V OUT V IN true average responding detector scheme

4027A Power Sensor

LP Filter 4027F Power Sensor

4027A Power Sensor

4027A10M Serial # Power Levels (kW) % Error 4027A Typical Linearity, MHz

4027A Typical Linearity, 12 MHz

Short Term Drift at Elevated Power Level

4028A 1-5/8” or 3-1/8” Transmission Line Higher Power 4028 Capability Similar Accuracy To Other 4027 Models Uses Larger Transmission Line (1-5/8” or 3-1/8”) Flanged or Unflanged Power Measurement Capability Up To 40Kw

Typical Field Power Measurement Systems

Source Amplifier Directional Coupler High Power Termination Forward watts Reverse watts Wattmeter p2p2 p1p1 p1p1 p1p1 p2p2 p2p2 A Typical Power Measurement Setup Utilizing a Directional Coupler

Coupler Based Measurements Advantages: Typically not limited by power- very little power dissipated Typically have good thru line reflection coefficients Forward Power readings are basically isolated from load stability issues Allows in-line monitoring of signal with actual system load Disadvantages: Must know the coupling value very accurately Directivity limits reflected power reading Frequency bandwidth limited

Source Amplifier Attenuator Forward watts Wattmeter Knowledge of the attenuation factor and stability is crucial to making a precise power measurement A Typical Power Measurement Setup utilizing an Attenuator and Thermal Power Meter Thermal Sensor

Assuming nominal attenuation value can lead to significant errors Errors can be minimized by calibrating the attenuator at the specific frequency or band of frequencies Attenuators and Their Effect On Accuracy Attenuators and Their Effect On Accuracy

Attenuator Based Measurements Advantages: Wideband frequency response, DC coupled Convenient to use, eliminates a termination Disadvantages: Limited in power dissipation Attenuation accuracy is often not precise, not as stable Reflection coefficients are generally higher

Attenuator Based Measurements Uncertainties Associated With This System –Input Mismatch Uncertainty (Typically Small Due to Low Input VSWR) –Output Mismatch Uncertainty –Uncertainties Associated With Thermal Power Meter –Attenuation Factor Uncertainty –Stability of Attenuation Factor Over Temperature –Additional Thermal Errors Due To Excessive Load Temperatures Affecting Thermal Power Sensor When an attenuator is used, obtain the calibrated attenuation factor from the manufacturer (or make the measurement yourself) for best possible precision measurements.

Summary National Standards Traceability- Challenges & Bird’s Solution –Bird’s multi-path solution and test capabilities make it unique in the industry RF Metrology Paths at Bird Electronic Corporation –High accuracy transfer of standards at every step of the way –Know the concepts behind the error sources in a test setup 4020 Series Power Sensors and the 4421 Power Meter –+/- 1% power sensor ideal for semiconductor industry Typical Field Power Measurement Systems –Know your system and the errors associated with it