TLP What is it Why is it used

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

Overview 1. What is TLP? 2. What data does TLP provide you with? 3. What information can TLP pulse variants provide? 4. Additional Measurements during TLP 5. How TLP works? 6. TLP Measurements 7. Q&A 2

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 3

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. 1 k. V 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 - 4 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

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

Section 2: What data does TLP provide you with? • Standard TLP (100 ns pulse width) • Emulates the energy seen in a Human Body Model (HBM) ESD event • With the use of sequential 100 ns 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 -10 ns 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 6

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 different energy levels effect the protection structure designs • Pulse Risetimes • The risetime of standard TLP is ~200 ps • Risetimes can be adjusted using risetime filters • Using different risetimes can determine whether the protection structure is effected by the different ramp rates 7

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, 1 kΩ Impedance uses High-Z Time Domain Reflection and Transmission (TDR-T) - DUT in series with pulse transmission path 8

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 9

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 TLP different than Curve Tracing? • Curve Tracing is DC • TLP is a short pulse • Shorter pulse • Reduced duty cycle, less heating • Controlled Impedance • Allows device behavior to be observed (more on this later) 10

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

TLP Waveforms • What variations are there for TLP waveforms? • Pulse Width • 100 ns • 30 ns – 500 ns Pulse Width • VF-TLP: 1 ns – 10 ns • Rise Time • 0. 2 ns – 10 ns Rise Time 12 Rise Time

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

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 14

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 15

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

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 17

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

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 19

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 20

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

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 22

Section 6 TLP Measurement • How devices are measured 23

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

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

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

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) 27

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

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 29

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

Thermo Scientific Questions? 31

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 32