for Microelectronics Packaging Dave Vallett PeakSource Analytical, LLC Fairfax, Vermont, USA

Transcription

1 Technology Advanced Quality, Fault Worldwide Isolation Analytical Services, Techniques Burlington VT for Microelectronics Packaging Dave Vallett PeakSource Analytical, LLC Fairfax, Vermont, USA

2 Purpose Highlight the importance of rapid problem solving during technology development, manufacturing, and end-user service Summarize the challenges of non-destructive localization of electrically active faults in dense assemblies Review techniques and recent advancements IBM Research 5/5/15 D. Vallett, PeakSource Analytical, LLC 2

3 Outline Introduction Microelectronic package fault isolation challenges Limitations of acoustic and X-ray imaging Methods EOTPR electro-optical terahertz pulsed reflectometry Lock-in thermography Magnetic current imaging Summary and Conclusions 5/5/15 D. Vallett, PeakSource Analytical, LLC 3

4 Fault Isolation - the Most Critical Step Development failures, yield loss, field returns Failure Analysis Verification & characterization Fault isolation Deprocessing Inspection Physical & chemical analysis 5/5/15 D. Vallett, PeakSource Analytical, LLC 4

5 Density Challenges in NDE Package-on-Package IBM Research Sub-surface imaging limited by opacity, absorption, thickness, heterogeneous materials, numerous interfaces Physical imaging alone (e.g. X- ray, acoustic) leaves electrically active defects indistinguishable from inert anomalies Needle in haystack challenge 5/5/15 D. Vallett, PeakSource Analytical, LLC 5

6 Acoustic, X-ray Image only Physical Structure Active defects, anomalies, structures, interfaces imaged simultaneously (2D or 3D) No definitive causality with electrical failure mode Subsequent analysis (e.g. cross-section, SEM) time-consuming, expensive, not definitive, destructive Precise, accurate, non-destructive fault isolation required 5/5/15 D. Vallett, PeakSource Analytical, LLC 6

7 Isolating Electrically Active Faults TeraHertz TDR Lock-in Thermography Sensor Magnetic Current Imaging 5/5/15 D. Vallett, PeakSource Analytical, LLC 7

8 Time Domain Reflectometry TDR / EOTPR (P. Perdu, EUFANET / IPFA 2012) Package conductors have transmission line characteristics Defects alter characteristic impedance Opens: cracks notches, resistive films, etc. Shorts: extra conductor material, foreign material, etc. Impedance changes cause reflections Reflection time correlates to distance Electro-optical TeraHertz pulsed reflectometry (EOTPR) significantly improves resolution 5/5/15 5/5/15 D. Vallett, D. Vallett, PeakSource Analytical, LLC LLC 8

9 EOTPR Cracked Substrate Trace Resolution / accuracy < 10 um (P. Perdu, EUFANET / IPFA 2012) 5/5/15 D. Vallett, PeakSource Analytical, LLC 9

10 EOTPR Flip-Chip Open Circuit 83 um (P. Perdu, EUFANET / IPFA 2012) 5/5/15 D. Vallett, PeakSource Analytical, LLC 10

11 Lock-in Thermography (LIT) Images surface thermal gradient from sub-surface heat source Pulsed source with lock-in amplification Signal depth derived from phase delay Absolute depth using thermal diffusion constants Relative depth using reference heat source(s) Resolution: single microns Sensitivity: micro-watts 5/5/15 D. Vallett, PeakSource Analytical, LLC 11

12 Thermal Phase-delay Estimates Defect Depth (H. Deslandes, DCG Systems) 5/5/15 D. Vallett, PeakSource Analytical, LLC 12

13 LIT BGA Pin Short, Fused Bond Wires (H. Deslandes, DCG Systems) 5/5/15 D. Vallett, PeakSource Analytical, LLC 13

14 LIT Depth Estimation in Stacked Die 13-ohm pin-pin short Fwd-biased diodes as depth references Depth correlates with phase-shift (H. Deslandes, DCG Systems) 5/5/15 D. Vallett, PeakSource Analytical, LLC 14

15 Magnetic Current Imaging (MCI) Sensor Magnetic field from buried currents propagates freely to the surface Magnetic permeability relative to free space Al Si Cu W Pb Scanned magnetic sensor maps field distribution Magnetic field data converted to current density image High current density or abnormal current paths indicate defect location Resolution: single microns Sensitivity: nano-amps / femto-watts 5/5/15 D. Vallett, PeakSource Analytical, LLC 15

16 MCI Leadframe Pin-Pin Shorts (J. Gaudestad, Neocera) 5/5/15 D. Vallett, PeakSource Analytical, LLC 16

17 MCI PLCC / Flex Cable Shorts 5/5/15 D. Vallett, PeakSource Analytical, LLC 17

18 MCI - Plane-to-Plane MLC Short short (J. Gaudestad, Neocera) 5/5/15 D. Vallett, PeakSource Analytical, LLC 18

19 Power Short in Fully Assembled PCB Short (J. Gaudestad, Neocera) 5/5/15 D. Vallett, PeakSource Analytical, LLC 19

20 MCI Subtle Leakage Analysis in PCB Fail Good 5/5/15 D. Vallett, PeakSource Analytical, LLC 20

21 MCI - Open Circuits Magnetic field from standing wave current vanishes at open circuit location 5/5/15 D. Vallett, PeakSource Analytical, LLC 21

22 Broken Copper Trace in Substrate (J. Gaudestad, Neocera) 5/5/15 D. Vallett, PeakSource Analytical, LLC 22

23 Open Failure in the Die Region (J. Gaudestad, Neocera) 5/5/15 D. Vallett, PeakSource Analytical, LLC 23

24 Summary 5/5/15 D. Vallett, PeakSource Analytical, LLC 24

25 Conclusions 5/5/15 D. Vallett, PeakSource Analytical, LLC 25