System in Package – how to cope with increasing challenges?
Walter Mack, Infineon Regensburg November 2011
Outline
SiP – what challenges do we face in analytic labs Consequences for analytical instrumentation Consequences for people
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Is nature showing us the path?
From single specific cell to smart systems integration:
Nature Evolution Principle Evolution pressure Strategies Targets Set date
„3D is natural“
Industry
under evolution pressure:„Survival of the fittest“ living conditions of biotope
appl.requirements /market
adaption, redundancy of crucial functions, populating niches,… reproduce & expand species
fulfill function reliably, get business
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More than Moore System integration & codesign of digital processing, memories and analog functions, passives, RF, MEMS, sensors, power... System integration migrates from board level to package level (SiP) or chip level (SoC) „Packaging is taking on system integration“ source: A. Allen, ITRS meeting, Japan Dec 2007
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How do the „species“ in industry look like ?
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TPMS (Tire Pressure Monitoring System)
MEMS Sensor
X-Ray
Potential next step towards „more 3D“: place ASIC on top of MEMS sensor
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Waferlevel packaging becomes 3 dimensional Reconstitution
Redistribution (RDL thin film technology)
Ballattach
Infineon wafer level package eWLB
conventional eWLB
“double sided eWLB”
Singulation
29.12.2011 Set date
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Via interconnect technologies Through Silicon Via (TSV)
500 µm
“Through Encapsulant Via” (TEV)
“Through Laminate Via” Chip embedding in PCBs
29.12.2011
Summarized trends we observe Diversity of technology
Convergence of IC/Package/PCB technology
Various analog & digital specific IC technologies (memories, RF, processors, power…) MEMS (sensors, actuators…) Passives Wafer level packaging Chip embedding in laminate Through silicon via & through encapsulant via Further shrink of interconnects (fine pitch wire bond, thinfilm technology, TSV) Integration of passives or functions in RDLs/TSV
3D designs
Stacked die approaches Multiple stacks of sub-packages, interposers… PoP (package on package) MEMS
Complex material mix Demanding system reliability & thermal management Set date
Wide range of material properties (Si, metal, ceramics, polymers, composites etc.) Expansion towards high reliability applications (automotive, aviation & space, power distribution, medical…) High reliability of system requires even higher reliability of sub components!
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What does it mean for our analytic methods ?
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Running production ¬ Quality & yield ¬ Inline-tools, sampling, monitoring
Customer returns, field failures 29.12.2011
reactive
Final product development & qualification ¬ Get 1st qualified product shipped to our customer
Business impact of faliures
Technology & assembly process development ¬ Mature interconnect technology ¬ Robust production processes ¬ Efficient material set
preventive
Early technology concept phase ¬ Assess new failure mechanisms, physics of failure ¬ Design for reliability & virtual prototyping (FEM Simulation)
Preferrably spent ressources & invest
Impact of Analytical Methods
Consequences for analytical instrumentation SiP Trend
Trend in FA
derived consequences
Diversity of technology
Diversity and mixture of methods
Large variety of methods to combine Enable highly flexible FA flows Software/interfaces for shared data utilization
Convergence of IC/Packaging/PCB technology
Convergence of IC /package level methods
IC localization methods to overcome encaps. Pkg methods to handle „IC dimensions“ IC prep. methods to handle „Pkg dimensions“
3D designs
„FA goes 3D“
3D localization methods 3D non-destructive imaging 3D navigation for prep.tools (e.g. FIB, laser)
Complex material mix
Complexity in preparation
Smart combination of various methods for decapsulation and target preparation develop more „universal“ methods
Demanding system reliability & thermal managem.
Advanced prediction capabilities
Combined measurement /simul. approaches Mat.characterization to setup material models Thermomech. stress characterization
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Typical analytical chain
1. Failure localization
X-ray, SAM, LIT, Magn.Micr.,OBIRCH…
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2. Preparation
Laser, milling, FIB, RIE…
3. Physical failure analysis
SEM, TEM, EDX, ToFSIMS, XPS,…
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4. (local) Materialcharacterization
EBSD, ESPI, Nanoindentation…
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Promising approaches FA Trend:
Examples for promising methods
„FA goes 3D“ Category:
Lock-in Thermography (LIT) -> Using phase shift -> Further development
Localization techniques SQUID scanning microscopy Further development of -> Sample tilt -> Multiple sensors? -> In 10ys: „SQUID tomography“? on substrate
X-ray CT -> Higher efficiency/ resolution -> Good vs. bad device comparison? -> Matching with reference CAD data? -> 3D geometrical mesh model for FEM -> In-situ scan during stress -> 3D image correlation -> Providing navigation data for prep.
on Chip
Flip Chip Pkg X-ray image
What else? Set date
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Example for 3D x-ray CT SiP device containing 2 Infineon chips
ca. 4 x 5 x 1.3 mm
Through vias
2x Flip chip Side view
side view Different pcb‘s X-ray top view
Passives at backside Solder balls Page 15
Example for 3D x-ray CT
Solder balls
Through vias
1. pcb layer FC1
2. pcb layer FC1
FC2 surface
FC1 bumps passives
1. pcb layer
2. pcb layer
3. pcb layer
Solder ball pads
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Promising Approaches FA Trend: Convergence of IC/package methods Category:
Examples for promising methods
Stacked dice laser milled
High precision laser milling -> Ablation of encapsulants & Silicon! (e.g. DPSS UV laser, ns-pulse)
Sample preparation
FIB cut, solder ball
High current FIB sources Further development of -> High ablation rates -> Able to handle thick polymers, Si, metal…
Combination of Laser & FIB -> Laser ablation followed by FIB polish -> 3D navigation: e.g. using x-ray CT data or SiP-CAD data Set date
Laser milling
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FIB polish
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Promising Approaches FA Trend: Demanding reliability & thermal managem. Category: Advanced prediction capabilities
Generally: Anything is good which supports finite element modeling at model generation, calibration, verification -> Thermomech. materialcharacterization -> Micromechanical testing (e.g. indentation, micro-compression/bending) -> Thermal deformation (e.g. image correlation, ESPI) -> etc.
Source: IWM Halle
3D image correlation -> Using deformation field e.g. from insitu x-ray CT (during thermal stress) Deformation of BGA solder balls 200°C vs. RT
Source: FhG ENAS, ITG Tagung ‘11
Raman stress map
Confocal Micro Raman Spectroscopy ->Stress characterization in Silicon
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Si chip dicing edge (cross section)
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What does it mean for people and lab management?
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Integrated systems require integrated teams
Systems in Package Techn. diversity
Systems of tools Tool diversity
Systems of brains Expertise diversity
Efficient knowledge management will be an essential success factor! Availability of multiple expertises and networking is crucial People with system knowledge and cross-functional thinking will be key players (we have to grow them ourselves…) Integrated teams (FA + Mat.characterization + Simulation) are beneficial Set date
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How to drive tool method development An application looks for it‘s analytical method Improve & adapt & combine the existing
Resolution, sensitivity, 3D capability, time efficiency
Combine measurement & simulation (inverse simulation)
An analytical method looks for it‘s application Discover the unknown
Benefit from progress in medical, forensic science, pharma, automotive, aviation…
Continuous scouting!
Dedicated budget & ressources for method development Share competencies & cost (e.g. funding projects) Live “best practice sharing” internally/externally Create a common “voice of industry” towards tool suppliers Set date
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Aspects of FA management
Management of „System Knowledge“ is crucial The increasing complexity of 3D SiP products leads to a tremendous invest to equip a „sufficient“ FA lab Higher management shall consider FA labs as an enabling function for next product generation – not just as a cost factor. Try to implement in early technology development phase: „Design for Analysis“ „Design for Testability“
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It‘s all about 3D…
Let‘s have an exciting workshop! Thank you for your attention!
„Waterfall“ 1961 by M.C.Escher, dutch graphic artist 1898-1972 Set date
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