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The Most Common Mistakes Made in Parametric TestPage 1 Bill Verzi Automated Test Group February 24, 2005 Common Mistakes of Parametric Test… … and how.

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Presentation on theme: "The Most Common Mistakes Made in Parametric TestPage 1 Bill Verzi Automated Test Group February 24, 2005 Common Mistakes of Parametric Test… … and how."— Presentation transcript:

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2 The Most Common Mistakes Made in Parametric TestPage 1 Bill Verzi Automated Test Group February 24, 2005 Common Mistakes of Parametric Test… … and how to avoid them!

3 The Most Common Mistakes Made in Parametric Test Page 2 Outline of Lecture Introduce Semiconductor Manufacturing and Test Using electrical test to evaluate semiconductor process features Top Ten List of Common Mistakes, and how to avoid them!

4 The Most Common Mistakes Made in Parametric TestPage 3 Section 1 An Introduction to D.C. Parametric Test Engineering

5 The Most Common Mistakes Made in Parametric Test Page 4 Why Parametric Test MOSFET Id equation Capacitance Resistivity

6 The Most Common Mistakes Made in Parametric Test Page 5 The big secret! This is the easiest test there is... Ohms Law R=V/II=V/RV=IR Test Structures are variants of: Diodes Resistors Capacitors Transistors But we measure these devices very carefully!

7 The Most Common Mistakes Made in Parametric Test Page 6 Environment where DC Parametric Test Systems are Used Clean Room Automatic Wafer Prober Bunny suits Darn good DC Parametric Test System

8 The Most Common Mistakes Made in Parametric Test Page 7 What do we measure? Semiconductor Wafers in Laboratories

9 The Most Common Mistakes Made in Parametric Test Page 8 What do we measure? Semiconductor Wafers in Production Minor flat Test Die Wafer ID Major flat Die or Chip Alignment target In-scribe test pattern Pad xxxx-xxxx-xx-x Scribe line Scribe Line TEG

10 The Most Common Mistakes Made in Parametric Test Page 9 A CMOS Cross-Section

11 The Most Common Mistakes Made in Parametric Test Page 10 DC Parametric Test for Front End Defects, Design Rules, Performance, and Reliability Metal 1 contact resistance, 1st insulator bridge and space Contact to gate space design rule Junction leakage and Breakdown Transistor Vt, Gm, Rds, Ids, Vpt, Peak Isub, Bvdss Thick Field Vt Mobile Ion, Latch-up Oxide Integrity, Qbd, Bulk impurities, TDDB, Well capacitance and resistance Poly and silicide resistance, Junction spiking Tungsten and interface resistance, Contact size and alignment

12 The Most Common Mistakes Made in Parametric Test Page 11 DC Parametric Test for Back End Defects, Design Rules, and Reliability Insulation breakdown, Back-end contamination tests, Intra and Inter-Layer bridging and space design rules Metal resistance, Width and space design rules, Electromigration Contact size and alignment, Contact and interface resistance Metal width and space design rules, Metal bridging and continuity

13 The Most Common Mistakes Made in Parametric Test Page 12 Statistical Process Control and Parametric Test All of these structures, all of these methods … and the wafers are very large! Plus my cycle times are not even close to 90 days Im lucky to get 3 information turns per year! How can I handle all of this data to be sure I get it right? Statistical Process Control is the means by which we handle this job!

14 The Most Common Mistakes Made in Parametric Test Page 13 What is Statistical Process Control? Parameter statistical samples ( Mean, Sigma, Range, … ) Information turns

15 The Most Common Mistakes Made in Parametric Test Page 14 Resolution and the bins of the normal distribution Low Resolution rejects good die High Resolution passes good die Vt to.01 V Vt to.005 V

16 The Most Common Mistakes Made in Parametric Test Page 15 The Nature of Repeatability Low Accuracy High Accuracy Low RepeatabilityHigh Repeatability

17 The Most Common Mistakes Made in Parametric Test Page 16 Lord Kelvin had something to say about statistics and measurement... I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it … But when you can not measure it, when you can not express it in numbers, your knowledge is of a meager and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely, in your thoughts, advanced to the stage of science, whatever the matter may be. William Thomson,Lord Kelvin, 1883

18 The Most Common Mistakes Made in Parametric Test Page 17 Top Six Reasons for Using DC Parametric Test on Electrical Test Structures Key Element in the rapid development of new process and new IC Allow Accelerated Testing and measurement of parameters for reliability models Provide a divide and conquer approach to semiconductor fabrication by allowing the measurement of fundamental quantities Facilitate a Kelvinist approach to processing by expressing results in numbers thus leading to clear decision making Provide a common link between fabs to judge and improve process quality Key element when transferring fabs to a new location By Martin G. Buehler

19 The Most Common Mistakes Made in Parametric Test Page 18 In Summary DC Parametric Test is used for… n For fast development of new manufacturing processes and devices n For fast release of new processes and devices to production lines n For fast yield enhancement and process optimization to minimize process cost n For achieving higher process technology and device reliability n And semiconductor process control requires statistical: n accuracy n repeatability n resolution n We must be careful when making measurements, we cant make mistakes!

20 The Most Common Mistakes Made in Parametric TestPage 19 Section 2 The Most Common Mistakes Made in Parametric Test* *And How to Avoid Them

21 The Most Common Mistakes Made in Parametric Test Page 20 The Top Ten List 1.Improper triaxial to coaxial adapters 2.Connecting SMUs up using the Sense line instead of the Force line 3.Improper connection on ground unit (GNDU) 4.Using Limited Auto ranging instead of Auto ranging 5.Using Default (Maximum) Current Compliance When Making Measurements in Auto or Limited Auto ranging 6.Not using SMU pulse mode, fixed measurement range, and/or Kelvin mode for high-power measurements 7.Using Auto ranging in Time Sampling Mode (4155/4156) 8.Improperly connecting SMUs in parallel 9.Failure to account for electro-motive force (EMF) on sensitive voltage measurements 10.Improper Capacitance Measurement Techniques When Using a Switching Matrix

22 The Most Common Mistakes Made in Parametric TestPage 21 Mistake #1: Improper triaxial to coaxial adapters

23 The Most Common Mistakes Made in Parametric Test Page 22 Shield (Ground) Guard Force Shield (Ground) Force Vg Coax Cables MOSFET Subthreshold Id fA pA nA uA mA Eliminate cable leakage and charging currents. Vg Triax Cables MOSFET Subthreshold Id fA pA nA uA mA Leakage Why Use Triax Cables? Required For Measurements < 1nA.

24 The Most Common Mistakes Made in Parametric Test Page 23 x1 Buffer SMU DUT Force V Guard Rs 10K Triaxial Guard Connection Simplified Diagram The guard voltage tracks the force voltage exactly. Cable charging current and noise is eliminated. Do not ever short the guard to the force line or shield line.

25 The Most Common Mistakes Made in Parametric Test Page 24 How Do I Connect Triaxial and Coaxial Connections? What do I do with the driven guard? ??? Does the current I am measuring affect how I connect to a BNC connector? Force / Sense Line Driven Guard Ground Shield Signal Where can I get the necessary TRIAX to BNC connectors?

26 The Most Common Mistakes Made in Parametric Test Page 25 Triaxial to Coaxial Adapters: Measuring Currents > 1 nano-Amp In this case it is OK to float the guard connection, since current leakage between the center conductor and the outer ground shield does not significantly impact the measurement.

27 The Most Common Mistakes Made in Parametric Test Page 26 Triaxial to Coaxial Adapters: Measuring Currents < 1 nano-Amp The only way to maintain low-current measurement accuracy in a coaxial environment is to connect the driven guard to the outer shield of the coaxial connector. This presents a potential safety hazard and must be done with great care. Warning! Shock Hazard!

28 The Most Common Mistakes Made in Parametric Test Page 27 Summary of Agilent Connectors

29 The Most Common Mistakes Made in Parametric TestPage 28 Mistake #2: Connecting SMUs up using the Sense line instead of the Force line

30 The Most Common Mistakes Made in Parametric Test Page 29 Most SMUs Have Both Force & Sense Outputs – Which Do I Use? If making Kelvin measurements, use both the Force and Sense outputs SMU Force OutputSMU Sense Output If not making Kelvin measurements, always use the Force output (never use the Sense output by itself)

31 The Most Common Mistakes Made in Parametric Test Page 30 x1 Buffer SMU Guard Sense DUT Force V Rs 10K Guard and Kelvin Connection Simplified Diagram The sense line is added. Cable resistance error is eliminated. Useful if the DUT <50 Ohms.

32 The Most Common Mistakes Made in Parametric Test Page 31 Do Not Use SMU Sense Output by Itself! SMU Force Circuitry SMU Sense Circuitry ~10 K SMU Force Output SMU Sense Output High Impedance Source / Monitor Unit (SMU): I out

33 The Most Common Mistakes Made in Parametric Test Page 32 x1 Buffer SMU Guard Sense Force V Source Gate Drain Substrate Measure Gate Voltage versus Time Accurately Triax to Coax Adapter (guard floating) To Scope Nifty Trick: Use the Sense Line as a High Impedance Scope Probe!

34 The Most Common Mistakes Made in Parametric TestPage 33 Mistake #3: Improper connection on ground unit (GNDU)

35 The Most Common Mistakes Made in Parametric Test Page 34 What is the Ground Unit (GNDU) Configuration? Sense Line Force Line Ground Shield Force / Sense Line Driven Guard Ground Shield Standard Triaxial Connection:Ground Unit Connection:

36 The Most Common Mistakes Made in Parametric Test Page 35 Why is the GNDU Configuration the Way It Is? Shield (Ground) Force Sense ??? In standard triaxial connections the middle conductor is a driven guard, which eliminates any cable leakage current by always keeping the driven guard the same potential as the center Force/Sense line. In the case of the ground unit the potential of the Force and Sense lines is always at zero volts, so there is no need to shield it from the outer ground shield to prevent leakage currents.

37 The Most Common Mistakes Made in Parametric Test Page 36 What Happens if I Connect the GNDU to a Standard Triaxial Connection? Connecting a standard triaxial connector to the GNDU without an adapter is equivalent to connecting up to the SMU Sense output ! I sink GNDU Force Circuitry GNDU Sense Circuitry ~10 K High Impedance Ground Shield Force Line Driven Guard Ground Shield Force Sense

38 The Most Common Mistakes Made in Parametric Test Page 37 Proper GNDU Connection Unless your equipment is designed to handle the GNDU connection, you must use an adapter that splits out the GNDU Force and Sense lines into standard triaxial configurations. The Agilent N1254A-100 Ground Unit to Kelvin Adapter will split the Force and Sense lines into the proper Kelvin configuration. GNDU Sense Output Force Output

39 The Most Common Mistakes Made in Parametric Test Page 38 Connections to the GNDU Should be Kelvin Remember! Pumping large currents through cables will cause an Ohmic drop unless this is compensated via a Kelvin measurement configuration. Since assumedly the reason you are using the GNDU is to sink large currents, you should always connect up both the Force and Sense lines. GNDU Sense Output Force Output I sink (Up to 4 Amps*) I sense (0 Amps) *E5270A

40 The Most Common Mistakes Made in Parametric TestPage 39 Mistake #4: Using Limited Auto ranging instead of Auto ranging

41 The Most Common Mistakes Made in Parametric Test Page 40 Ranging – What is It? 10 pA 100 pA 1 nA 10 mA 100 mA Fixed Ranging – Always stay in the same measurement range Limited Ranging – Never go below the specified range limit Auto Ranging – Go as low as necessary to make an accurate measurement (down to the lowest range supported if necessary)

42 The Most Common Mistakes Made in Parametric Test Page Example The 4156 has two additional low-current measurement ranges not available on the 4155: 100 pA & 10 pA The 4156 boots-up like a 4155C (all SMUs set to Limited 1 nA ranging) Unless these are changed, you cannot get the full low-current measurement capability of the instrument!

43 The Most Common Mistakes Made in Parametric Test Page 42 ID-VG Low-level Subthreshold Measure Setup Page - Default These are 4156 default settings at boot-up Measurements are made quickly but noise level is high. Notice the LIMITED 1nA settings. These are 4155 defaults.

44 The Most Common Mistakes Made in Parametric Test Page 43 ID-VG Low-level Subthreshold Probes Up - Default Range Setting Noise level is high. Current measurement is limited to the 1nA range.

45 The Most Common Mistakes Made in Parametric Test Page 44 ID-VG Low-level Subthreshold Measure Setup Page - AUTO range Set the drain SMU range setting to AUTO. This uses the two lower ranges of the 4156 and decreases the noise floor by 100x.

46 The Most Common Mistakes Made in Parametric Test Page 45 ID-VG Low-level Subthreshold Probes Up - ZERO Check Integration time can be short. Wait 30 minutes after boot up of If the trace is not centered at 0 fA, press the GREEN key and Zero key to remove offset error. +/- 2fA variation is the typical noise floor of the instrument by itself (no cables attached).

47 The Most Common Mistakes Made in Parametric Test Page 46 Extend Resolution 100X 4156C Display Page This feature is only available in the 4156C. You can upgrade a 4156B to a 4156C. 1 fA resolution 0.01 fA resolution

48 The Most Common Mistakes Made in Parametric Test Page 47 ID-VG Low-level Subthreshold Curve Probes Down C Graph Page Low leakage characteristics of a 40 Angstrom thick oxide n-channel MOSFET. Resolution is.01 fA ( Amps)

49 The Most Common Mistakes Made in Parametric TestPage 48 Mistake #5: Using Default (Maximum) Current Compliance When Making Measurements in Auto or Limited Auto ranging

50 The Most Common Mistakes Made in Parametric Test Page 49 Where Does the Range Search Start? 10 pA 100 pA 1 nA 10 nA 100 mA For Auto Ranging and Limited Ranging, the range search starts at the value you set for compliance. Therefore, if you are measuring a small current and you do not change the default compliance setting (100 mA in this example), then the instrument will take longer to reach its final measurement range.

51 The Most Common Mistakes Made in Parametric Test Page 50 How Do I Change This? 10 pA 100 pA 1 nA 10 nA 100 mA If you know that you are measuring a small current and you want to use Auto ranging, then reduce the value of the compliance to a smaller value to speed up the measurement. In this case, compliance was reduced to 10 nA (since a current level below 1 pA was expected).

52 The Most Common Mistakes Made in Parametric Test Page 51 Changing the 4155/4156 Compliance Settings Reduce the compliance settings to speed up your low-current measurements

53 The Most Common Mistakes Made in Parametric Test Page 52 Remember! Need AUTO Ranging for Low Current Keep in mind that reducing the compliance speeds up your measurement, but you still need to be using AUTO ranging in order to measure low currents (fA level)

54 The Most Common Mistakes Made in Parametric TestPage 53 Mistake #6: Not using SMU pulse mode, fixed measurement range, and/or Kelvin mode for high-power measurements

55 The Most Common Mistakes Made in Parametric Test Page 54 SMU Pulsed Mode Reduces Thermal Heating Error

56 The Most Common Mistakes Made in Parametric Test Page 55 Kelvin Sensing Eliminates High Power Measurement Error

57 The Most Common Mistakes Made in Parametric Test Page 56 Using SMUs in Pulsed Mode Channel Definition Page Press the VPULSE softkey to define the voltage pulse mode. In this case the gate SMU will be pulsed. Note: Only ONE SMU can be in pulsed mode.

58 The Most Common Mistakes Made in Parametric Test Page 57 SMU Pulsed Mode Example of Pulsing The Primary Source VAR1 Primary Source VAR2 Secondary Source Only one SMU can be pulsed. Minimum width is 0.5 ms (includes the time to make a 5-digit resolution measurement).

59 The Most Common Mistakes Made in Parametric Test Page 58 Using SMUs in Pulsed Mode Power MOSFET Measure Page A SMU PULSE menu appears. Here the duty cycle of the pulse is set at 10%. Change the PERIOD to 100ms to reduce heating further. The device will be powered on only 1% of the time.

60 The Most Common Mistakes Made in Parametric Test Page 59 Using SMUs in Pulsed Mode Measure Setup Page VERY IMPORTANT! Use FIXED ranges. FIXED prevents the SMUs from auto ranging. AUTO over- rides the pulse settings and could add up to 30ms on each range change. Here Id is set to the 1Amp range to make use of the HPSMU in the expander box.

61 The Most Common Mistakes Made in Parametric Test Page 60 Using SMUs in Pulsed Mode Graph Page VERY IMPORTANT! Use SHORT integration. This minimizes heating and assures proper timing. LONG integration will over-ride your pulse width/length setting. Much more time is required for long integration.

62 The Most Common Mistakes Made in Parametric Test Page 61 Kelvin Triax Cable Ideal for both low current and low impedance applications. Guard Force Ground Sense +- I Force SMU1 (Force) SMU2 (Force) SMU1 (Sense) SMU2 (Sense) V Sens e I=0

63 The Most Common Mistakes Made in Parametric Test Page 62 Non-Kelvin Measurements Can Introduce Significant Error Slope = 1/Re (Kelvin) Slope = 1/(Re+Rcable) (Non-Kelvin) I B Re = 0.55 Rcable = 0.40 V C monitor Cable resistance comparable to resistance being measured

64 The Most Common Mistakes Made in Parametric Test Page 63 To Kelvin Probe To Guarded Chuck Wafer Prober Kelvin Cable Connections Optimized For Measurement Accuracy

65 The Most Common Mistakes Made in Parametric TestPage 64 Mistake #7: Using Auto ranging in Time Sampling Mode (4155/4156)

66 The Most Common Mistakes Made in Parametric Test Page 65 What is Time Sampling? Initial Interval Time 60 s to 65 sec (4155/4156) Time sampling involves measuring a voltage or current at regular intervals over time. Useful for certain types of reliability stress measurements such as Time Dependent Dielectric Breakdown (TDDB)

67 The Most Common Mistakes Made in Parametric Test Page 66 Specifying a Small Sampling Interval and Auto Ranging Creates a Conflict! Time sampling inherently requires that the measurement occur within a certain time period. Otherwise, the sampling rate cannot be met. Auto ranging requires the instrument to start at the specified compliance value and work its way down to the correct measurement range, which takes time. Specifying both a short sampling time (fast sample rate) and auto ranging creates a conflict for the instrument!

68 The Most Common Mistakes Made in Parametric Test Page 67 How Does this Conflict Get Resolved? Accuracy always wins out over speed The instrument will take as long as necessary to auto range, ignoring the specified measurement interval settings The end result is that the instrument will not measure at the interval you specified! NEVER USE AUTO-RANGING WHEN MAKING FAST TIME SAMPLING MEASUREMENTS

69 The Most Common Mistakes Made in Parametric Test Page 68 How Do I Optimize My Time Sampling Measurements? ??? Besides using FIXED ranging, what else do I need to do to optimize my Time Sampling measurements? Minimize active units Measure on only one resource Disable the STOP condition Minimize the compliance setting

70 The Most Common Mistakes Made in Parametric Test Page 69 Optimizing Time Sampling Measurements - 1 Minimize the number of active resources to only those that you need.

71 The Most Common Mistakes Made in Parametric Test Page 70 Optimizing Time Sampling Measurements - 2 Make sure that compliance is set as low as possible For intervals < 2 ms, must have STOP CONDITION set to DISABLE For intervals < 2 ms, can only have one measurement channel

72 The Most Common Mistakes Made in Parametric Test Page 71 Optimizing Time Sampling Measurements - 3 For intervals < 2 ms, must used FIXED measurement range (never use AUTO ranging).

73 The Most Common Mistakes Made in Parametric TestPage 72 Mistake #8: Improperly connecting SMUs in parallel

74 The Most Common Mistakes Made in Parametric Test Page 73 Why Would I Connect SMUs in Parallel? ??? Connecting SMUs in parallel allows you to increase the total current delivered to a DUT SMU 1SMU 2DUT I Total = I SMU1 + I SMU2

75 The Most Common Mistakes Made in Parametric Test Page 74 I Force, V Measure (Non-Kelvin Connection) Easy to do: Can control with I/CV Voltage measurement accuracy is relatively poor Force Sense SMU 1 Vm Force Sense SMU 2 DUT Vm

76 The Most Common Mistakes Made in Parametric Test Page 75 I Force, V Measure (Kelvin Connection) Easy to do: Can control with I/CV High voltage measurement accuracy Force Sense SMU 1 Vm Force Sense SMU 2 DUT Vm

77 The Most Common Mistakes Made in Parametric Test Page 76 Current Force Mode is not Always Useful Force Sense SMU Vm Paralleling SMUs in current source mode is easy, BUT: Not all applications can be covered this way It begs the question of how to parallel SMUs in voltage force mode

78 The Most Common Mistakes Made in Parametric Test Page 77 V Force, I Measure (Non-Kelvin Connection) Voltage force accuracy is poor Easy to use in concept, BUT requires great care to prevent two voltage sources from interfering with one another A Force Sense SMU 1 A Force Sense SMU 2 DUT

79 The Most Common Mistakes Made in Parametric Test Page 78 V Force, I Measure (Kelvin Connection) High voltage force accuracy Requires sophisticated measurement control software A Force Sense SMU 1 Vm Force Sense SMU 2 DUT

80 The Most Common Mistakes Made in Parametric TestPage 79 Mistake #9: Failure to account for electro-motive force (EMF) on sensitive voltage measurements

81 The Most Common Mistakes Made in Parametric Test Page 80 Thermo Electro-Motive Force (EMF): What is It? A transient voltage pulse that is associated with reed relay switches. Note: This is NOT an example of the relays used in our instrumentation.

82 The Most Common Mistakes Made in Parametric Test Page 81 Agilent 4073A/B Relays Eliminate Thermo-EMF Agilent 4073A example through the switching matrix

83 The Most Common Mistakes Made in Parametric Test Page 82 Managing the Use of a Reed Relay Switch Complete the measurement as quickly as possible. – Complete the measurement within 10 seconds. This keeps the total drift to less than a few micro-volts. Wait until the thermo-EMF has stabilized to its final value. – For the 4156C and E5270, set the SMU output relay to its on (closed) state after warm-up and keep it there.

84 The Most Common Mistakes Made in Parametric Test Page 83 Kelvin Resistance Measurement Key Points: 1)Make sure that you eliminate Joule self- heating effects 2)Measure and subtract Voffset 3)Measure twice with opposing current flow and average the two resistances R = (V M1 – V M2 )/I F VMU 2 (SMU 4) SMU 2 VMU 1 (SMU 3) SMU 1 R Force Current Twice (Both Ways), i.e. +/- I F V M1 V M2 0 V VMU 1 (SMU 3) V M1 V EMF 1 V OFF VMU 2 (SMU 4) V M2 V EMF 2 V OFF

85 The Most Common Mistakes Made in Parametric TestPage 84 Mistake #10: Improper Capacitance Measurement Techniques When Using a Switching Matrix

86 The Most Common Mistakes Made in Parametric Test Page 85 Three Most Common Mistakes Using a Four terminal pair through a Switching Matrix: Hc Hp Lc Lp V A 2. Ignoring return path connection 3. Cable impedance not 50 Ohms. 1. Unsupported cable length (> 4 meters) MATRIX

87 The Most Common Mistakes Made in Parametric Test Page 86 Mistake 1: Unsupported Cable Length Causes Error Hc Hp Lc Lp V A 100pF/m 250nH/m If the cable length is too long, then the 4284A may not be able to balance its bridge! MATRIX The 4284A can only compensate cable lengths up to 4m The innate 4284A compensation routine only supports cable lengths up to 4 meters. Additional correction is needed for longer cable lengths.

88 The Most Common Mistakes Made in Parametric Test Page 87 Open/Short/Load Correction Model The built-in 4284A compensation algorithm extracts four parameters using three (open/short/load) measurements. C meter DUT I1I1 V1V1 I 1 CMH CML C meter DUT I1I1 I 1 CMH CML Guard Cables that are too long invalidate the assumptions. The number of port parameters becomes greater than four and the built-in 4284A compensation routine does not work. V2V2 I2I2 V2V2 I2I2 Assume I 1 =i 1 I 1 ~i 1 Ideal If the cable length is too long…

89 The Most Common Mistakes Made in Parametric Test Page 88 Limitation of OPEN/SHORT/LOAD correction Open/Short/Load correction is not perfect. Load impedance should be same range as the device impedance you want to measure. Typical parametric measurements are in this range.

90 The Most Common Mistakes Made in Parametric Test Page 89 Mistake 2: No Return Path Wire Causes Error Hc Hp Lc Lp V A Make return path near the device. Return wire stabilizes the cable inductance. Cable inductance can change from 250 nH/m to more than 400 nH/m by removing return wire. MATRIX Return Wire length is also important.

91 The Most Common Mistakes Made in Parametric Test Page 90 Mistake 3: Wrong Cable Causes Measurement Error Hc Hp Lc Lp V A Agilent Triaxial cable is not 50 Ohm 333 nH/m 250nH/m MATRIX The built-in 4284A correction routine supports only 50 Ohm cables. Need additional correction for cables that are not 50 Ohms. 4284A calibration routine expects 50 Ohm cable environment Matrix internal path is not 50ohm

92 The Most Common Mistakes Made in Parametric Test Page 91 Conclusions / Summary A little understanding can go a long way towards helping you improve your parametric measurement skills. More information is available in our Parametric Test Assistant CD (Agilent Publication # EN) Live phone-based assistance is available by calling Agilents US Customer Care Center at:


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