TLP What is it? Why is it used?

1. TLP What is it?Why is it used? April 2012

2. Overview • What is TLP? • What data does TLP provide you with? • What information can TLP pulse variants provide? • Additional Measurements during TLP • How TLP works? • TLP Measurements • Q&A

3. Section 1: What is TLP? • TLP (Transmission Line Pulsing) is a device characterization tool, used to gather detailed information about your protection structure designs • TLP uses a square wave pulse, in a controlled environment and measures the Voltage and Current values gathered during the pulsing • As it is a controlled environment, generally 50 ohms, the gathered data is repeatable, providing reliable information about your protection structure designs • Consecutive, increasing amplitude pulses are used to develop a string of Voltage and Current measurements, which are then used to provide data about your protection structures

4. Section 2: What data does TLP provide you with? • ESD testing provides limited data about your device, essentially it simply tells you where the protection structure fails, i.e. 1kV failure threshold • TLP provides detailed information about the protection structure • Parameters that can be captured include: • Turn on time (point in voltage when structure reacts) • Snapback voltage • RON resistance • Failure point • Why is this information important? • Characterization of protection structures is important • As it can help designers understand their protection structure designs • It can help predict behavior of the structure during actual ESD events • It can be used to qualify or predict new designs • It can be used to qualify designs on wafer or non-packaged devices

5. 4 3 2 1 Section 2: What data does TLP provide you with? • Device: Snapback Protection Structure 1. Low Voltage TLP Pulses • Open Circuit till turn-on time 2. Snapback Threshold • Begins conducting current • On Resistance • Failure Level • Peak Current

6. Section 2: What data does TLP provide you with? • Standard TLP (100ns pulse width) • Emulates the energy seen in a Human Body Model (HBM) ESD event • With the use of sequential 100ns TLP pulses, HBM characterization is possible. Device structures can be analyzed but can also be taken to failure. • Using TLP failure levels versus actual ESD test failure thresholds, correlation levels can be determined • Time Domain Reflection (TDR) is the main measurement technique used • VF-TLP (1-10ns pulse widths) • Emulates the event speed and the energy seen in a Charge Device Model (CDM) ESD event • Although the event is similar there are still questions on whether it truly replicates the event • Although VF-TLP testing may not replicate CDM events, it still provides useful data about the reaction protection structures using this fast event

7. Section 3: What information can TLP pulse variants provide? • Pulse durations • Longer or shorter pulse durations can be used and are accomplished by varying the length of the TLP cable • These will show how different energy levels effect the protection structure designs • Pulse Risetimes • The risetime of standard TLP is ~200ps • Risetimes can be adjusted using risetime filters • Using different risetimes can determine whether the protection structure is effected by the different ramp rates

8. Section 3: What information can TLP pulse variants provide? • Different Impedances and measurement techniques • Standard TLP impedance is 50 ohms • Uses a Time Domain Reflection (TDR) measurement technique • TDR-O (Overlapping) • TDR-S (Seperated) • Impedance can be changed to different resistance levels. • 25 ohms uses a Time Domain Transmission (TDT) measurement technique • 100 ohms uses a Time Domain Reflection and Transmission (TDR-T) measurement technique • DUT in series with pulse transmission path • 500Ω, 1kΩ Impedance uses High-Z Time Domain Reflection and Transmission (TDR-T) • DUT in series with pulse transmission path

9. Section 3: What information can TLP pulse variants provide? • Changing the Impedances and Measurement Techniques can provide additional information about the device protection structure • Low Impedance • More current flow for a given voltage • More voltage amplitude • High Impedance • Less current flow for a given voltage • Less voltage amplitude

10. Section 4: Additional Measurements during TLP In addition to the Voltage and Current data gathered from the TLP measurements, leakage or curve tracing measurements can also be captured • How is TLPdifferent than Curve Tracing? • TLP is a short pulse • Curve Tracing is DC • Shorter pulse • Reduced duty cycle, less heating • Controlled Impedance • Allows device behavior to be observed (more on this later)

11. Devices for TLP Testing • What kinds of packages can be tested? • Package Level • Wafer Level

12. Pulse Width TLP Waveforms • What variations are there for TLP waveforms? • Pulse Width • 100ns • 30ns – 500ns • VF-TLP: 1ns – 10ns • Rise Time • 0.2ns – 10ns Rise Time Rise Time

13. Pulse Width Rise Time TLP Waveforms • How do these variations affect the TLP test? • Pulse Width • Energy under the curve • Rise Time • Device reaction

14. Section 5: How TLP Works • How is a TLP waveform generated? • Transmission Line connected to power supply • Called Charge Line • Length proportional to pulse width • Power supply charges the cable

15. Section 5: How TLP Works • How is a TLP waveform generated? • DUT lies at end of another transmission line • Switch closes • Charge exits Charge Line, propagates towards DUT

16. Section 5: How TLP Works • How is a TLP waveform generated? • Square waveform • Charge Line behaves as a storage device

17. Section 5: How TLP Works • What happens when the waveform hits the DUT? • Recap: TLP is a short-duration pulse in a controlled-impedance environment • Behaves like an RF signal • RF signal behavior • Propagates until impedance changes

18. Section 5: How TLP Works • How is resistance measured with a TLP pulse? • Square pulse, perceive it as a short-duration Curve Trace TLP DC Curve Trace • Voltage and Current probes measure the DUT

19. Section 5: How TLP Works • How is resistance measured with a TLP pulse? • Plateau of waveforms are averaged • Device allowed to settle into “quasi-static” state

20. Section 5: How TLP Works • Why use both a Voltage probe and a Current probe? • It is possible to calculate DUT resistance with only 1 probe • VDUT = VPulse – (IDUT * ZTLP) • IDUT = (VPulse – VDUT) / ZTLP • Not desirable because extremes are noisy

21. Section 5: How TLP Works • Sequential TLP pulses produces an I/V Curve

22. Section 5: How TLP Works • How is the Pulse Width changed? • Length of cable • How is the Rise Time changed? • Low-pass filter added LP

23. Section 6 TLP Measurement • How devices are measured

24. Section 6: TLP Measurement • Measurement Goals • Capture Voltage at the DUT • Capture Current through the DUT

25. Section 6: TLP Measurement • Equipment to deliver TLP pulse to DUT • Wafer Level • DUT (on wafer) • TLP Pulse delivery cable • TLP Pulse delivery probe • Ground Probe • Ground Braid 3 2 5 1 • Package Level • DUT in socket • TLP Pulse delivery cable • Grounded pin 3 4

26. Section 6: TLP Measurement • Ideally, V and I probes are directly on DUT • Direct placement not possible V/I Probes

27. Section 6: TLP Measurement • Although probes are not at DUT, measurements are possible V/I Probes • Controlled impedance • Waveform observable any place along path • Time Domain Reflection (TDR)

28. V/I Probes Section 6: TLP Measurement • How are measurements accomplished away from DUT? • Incident and Reflected waveforms • Adding the waveforms reproduces DUT measurement • Incident and Reflected waveforms are recorded separately (TDR-S)

29. Section 6: TLP Measurement • TDR-S performs waveform addition with software V/I Probes • Waveform addition can also be done in the TLP circuit V/I Probes

30. V/I Probes Section 6: TLP Measurement • Overlapping waveforms • Incident and Reflected overlap, add together • Overlapped waveform plateau reproduces DUT waveform

31. Thermo Scientific Questions?

32. APT Management • Applications/Product/Technology Group Contacts: • Marcos Hernandez - Manager • marcos.hernandez@thermofisher.com, • Work: 408-481-4410 Mobile: 510-449-6493 • Tom Meuse • tom.meuse@thermofisher.com, Work:978-935-9322, Mobile:603-765-7556 • Ron Ahlquist • ron.ahlquist@thermofisher.com, Work:978-935-9328, Mobile:603-396-2680 • Ron Perry (Test Fixtures) • ron.perry@thermofisher.com, Work:978-935-9366, Mobile:603-479-4920