Polymers Hard at Work in Your Smart Phone Jeffrey T. Gotro, Ph.D. President and Founder InnoCentrix, LLC 9...
Dr. Jeffrey Gotro• Over 30 years experience in polymers in electronics (IBM, AlliedSignal, Honeywell, Ablestik Labs)• R...
Bell Labs versus Motorola Martin Cooper • Inventor of the cellular phone at ...
First Cell Phone (1973)Name: Motorola Dyna-TacSize: 9 x 5 x 1.75 inchesWeight: 2.5 poundsDisplay: NoneNumber of Circuit Bo...
Smart Phones pack a powerful punch • Phone • Email ...
Multiple Electronic “Packages” Package Types:HTC Evo 4G • QFP ...
Uses of Polymers in Packaging• Die attach adhesives (glue computer chips to carriers) – Conductive – Non-conductive ...
Polymers in Leadframe PackagesDepending on the metal leadframe used:• Epoxy-based die attach adhesives• BMI/acrylate die a...
Multiple Polymers Used Filled via’s Thermal Interface Laser drilled re-Heat Spreader ...
What is a Polymer?From the Greek word poly – meaning many and meros –meaning unitsMerriam – Webster online dictionary;“A c...
Polymers Can Have Many FormsLinearBranchedCrosslinkedor Network
Thermoplastic versus Thermoset Polymer Melt Polymer Heat ...
Thermoset PolymersEpoxy CH3Cyanate Ester N C O C ...
Examples of Different Network StructuresEpoxy Cyanate Ester Bismaleimide
Modulus vs Temperature for Polymers Glass Transition Melting Po...
Polymers in Semiconductor PackagingThere are some tough material requirements• Low viscosity to flow (die attach and under...
Thermosets Offer Wide Processing RangeMonomers/Oligomers Partially cured Fully Cured Network• Low viscosity...
Epoxy is Most Common Thermoset Adhesion, reactive Aromatic rings give high temperature ...
Types of EpoxiesBis Phenol EpoxyEpoxy novolacCycloaliphatic epoxy
Die Attach Adhesives• Die attach adhesives are typically needle dispensed – Rheological (flow) properties are critical ...
Die Attach Resin Technologies Epoxy ring opening• Epoxies, liquid epoxies• ...
Flow Curve – Uncured Filled Pastes 1.E+05 ...
Everyday Example of a Yield Point• With the old-style glass ketchup bottle, what happened when you turned it upside down?...
New Design• Squeeze bottle to apply stress• Overcome the yield point and get good flow• Shear fields in nozzle break up st...
Die Stacking Technology ProgressionStarted with paste die attach(using standard dispense tools) Migrated to f...
Die Attach Film Adhesives• Die stacking is main use for film-based die attach• Need precise control of bondline thicknes...
Flow Over Wire (FOW)• Rheological properties are modified to allow the resin to flow over and encapsulate the wires• Sam...
Multiple Die Stacks Use Film Adhesive Flow Over Wire
Polymers in a Flip Chip Package Underfill Chip Mold Compound Solder Balls L...
Underfill Processing • Underfill dispensed ...
Polymers are Key Integration Enablers UnderfillsThu-Via technology...
Mold Compound Technology• Epoxy cresol nolovak mold compounds (EMC) – Phenol novolak cured – Ease of processing, f...
Laminate Substrate Types• Double-sided – Typically used in wire-bonded applications – Largest volumes• Multilayer ...
Substrate Materials• Primarily BT resin (Mitsubishi Gas Chemical) – Bismaleimide/cyanate ester (triazine)/epoxy blend• H...
BT Epoxy Chemistry O O N CH2 N ...
Cell Phone Camera Module Four different adhesives in a camera module: 1. Conductive die attach adhesive ...
Summary• Polymers are key enabler in semiconductor packaging• Thermosets are extensively used – Low viscosity to enable ...
Contact Info Dr. Jeff Gotro InnoCentrix, LLC 22431 Antonio Parkway Suite B160-515Rancho San...
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Polymers hard at work in your smart phone imaps san diega march 2013

Published on: Mar 4, 2016
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Transcripts - Polymers hard at work in your smart phone imaps san diega march 2013

  • 1. Polymers Hard at Work in Your Smart Phone Jeffrey T. Gotro, Ph.D. President and Founder InnoCentrix, LLC 949-635-6916 www.innocentrix.com
  • 2. Dr. Jeffrey Gotro• Over 30 years experience in polymers in electronics (IBM, AlliedSignal, Honeywell, Ablestik Labs)• Recognized expert in thermosetting polymers• Ph.D. in Materials Science from Northwestern University, specialty in polymer science/ polymer physics• Founded InnoCentrix in 2008 – Technical and management consulting in thermosets/electronic materials. 2
  • 3. Bell Labs versus Motorola Martin Cooper • Inventor of the cellular phone at Motorola • First person to make a call on a portable cell phone on April 3, 1973 from the corner of 56th and Lexington in New York City • The first call he made was to his rival, Joel Engel, Bell Labs head of research.Bell Labs and Motorola were in a race to introduce the first cellular telephone
  • 4. First Cell Phone (1973)Name: Motorola Dyna-TacSize: 9 x 5 x 1.75 inchesWeight: 2.5 poundsDisplay: NoneNumber of Circuit Boards: 30Talk time: 35 minutesRecharge Time: 10 hoursFeatures: Talk, listen, dial
  • 5. Smart Phones pack a powerful punch • Phone • Email • Video • MP3 music player • Camera • High resolution screensSignificant processing power in a small package
  • 6. Multiple Electronic “Packages” Package Types:HTC Evo 4G • QFP • QFN • PBGA • Flip Chip
  • 7. Uses of Polymers in Packaging• Die attach adhesives (glue computer chips to carriers) – Conductive – Non-conductive – Dispensable paste and film formats• Underfills (flow under chips) – Capillary and wafer level (no-flow)• Mold compounds (encapsulate chips)• Laminate substrates (circuit connections) – Base laminate – Printed circuit boards• Camera Modules – Various types of adhesives
  • 8. Polymers in Leadframe PackagesDepending on the metal leadframe used:• Epoxy-based die attach adhesives• BMI/acrylate die attach adhesives QFN Mold Compound Die Die attach adhesive Lead finger Die Pad Lead finger Mold compounds are typically epoxy-based
  • 9. Multiple Polymers Used Filled via’s Thermal Interface Laser drilled re-Heat Spreader •Conductive Material distribution layers •non-conductive Epoxy lid attach Adhesive Capillary Underfill High density BT substrate soldermask • Polymer film redistribution layers • Bis-maleimide triazine epoxy (BT) laminate used in flip chip substrates • Epoxy/acrylate soldermask • Silicones/thermal greases in TIM materials • Epoxy or cyanate ester/epoxy used in capillary underfills
  • 10. What is a Polymer?From the Greek word poly – meaning many and meros –meaning unitsMerriam – Webster online dictionary;“A chemical compound or mixture of compounds formed bypolymerization and consisting essentially of repeatingstructural units.”As we will see, polymers gain their unique and usefulproperties by being long molecules with specific chemicalrepeat units.
  • 11. Polymers Can Have Many FormsLinearBranchedCrosslinkedor Network
  • 12. Thermoplastic versus Thermoset Polymer Melt Polymer Heat Cool Melt Heat Chemical Reaction Solid Solid X Monomers Crosslinked and Network Polymer Oligomers Cool Heat Melt• Polymer chains not linked • Polymer chains are crosslinked• Melted by heating cycles • Stable on heating 12
  • 13. Thermoset PolymersEpoxy CH3Cyanate Ester N C O C H O C N O OBismaleimide N R N O OAcrylate R
  • 14. Examples of Different Network StructuresEpoxy Cyanate Ester Bismaleimide
  • 15. Modulus vs Temperature for Polymers Glass Transition Melting Point Log E, dynes/cm2 Log E, Pa Temperature
  • 16. Polymers in Semiconductor PackagingThere are some tough material requirements• Low viscosity to flow (die attach and underfills)• Wide range of cure profiles – Thermal (oven, snap and spot cure) and UV cure – Partial cure (B-stage) for printable pastes and films• Tailored modulus depending on the application• Low coefficient of thermal expansion• High temperature stability for lead-free reflow profiles• Low moisture absorption
  • 17. Thermosets Offer Wide Processing RangeMonomers/Oligomers Partially cured Fully Cured Network• Low viscosity • B-staged • No flow• Good flow/dispensing • Film-like properties • Tailored Tg depending• Use various • Can still flow with on chemistry monomers to tailor additional heat • High temp stability properties • Controlled CTE• Reactive diluents to control viscosity
  • 18. Epoxy is Most Common Thermoset Adhesion, reactive Aromatic rings give high temperature site, wettability performance and rigidityEpoxy reactive site Epoxy reactive site Molecular weight Toughness Bisphenol A epoxy; X=H, for tetrabromobisphenol A; X- Br
  • 19. Types of EpoxiesBis Phenol EpoxyEpoxy novolacCycloaliphatic epoxy
  • 20. Die Attach Adhesives• Die attach adhesives are typically needle dispensed – Rheological (flow) properties are critical – Shear thinning, yield point• Base resins are typically monomers and oligomers• Reactive diluents used to lower viscosity, but react into the adhesive during curing• Additives – Adhesion promoters, conductivity promoters – Curing agents, catalysts• Fillers used to tailor properties – Silver flake for electrically conductive adhesives – Silica for non-conductive adhesives
  • 21. Die Attach Resin Technologies Epoxy ring opening• Epoxies, liquid epoxies• Acrylate monomers, oligomers Polymerize across• Reactive diluents the double bond – Acrylates and methacrylates• Bismaleimides (aliphatic, low viscosity)• Hybrid resins – Dual functionality (i.e. epoxy on one end and acrylate or bismaleimide on the other end) – Useful for controlling dual network formation
  • 22. Flow Curve – Uncured Filled Pastes 1.E+05 Yield Stress Steady-state Viscosity, h (Pas) 1.E+04 network aggregates 1.E+03 84-1 LMISR4 Resin and 1.E+02 filler eqn. Cross Yield-stress 1.E+01 Resin discrete particles 1.E+00 Resin is 1.E-01 Newtonian 1 10 100 1000 Shear Stress, s (Pa)
  • 23. Everyday Example of a Yield Point• With the old-style glass ketchup bottle, what happened when you turned it upside down? – No flow to your burger! (has yield point due to structure) – Hit the bottom of the bottle (apply stress to overcome the yield point) – If that failed, use a knife to stir the ketchup (break-up the structure and lower the yield point) – Flows OK onto burger
  • 24. New Design• Squeeze bottle to apply stress• Overcome the yield point and get good flow• Shear fields in nozzle break up structure and lower viscosity Good Flow To Burger!
  • 25. Die Stacking Technology ProgressionStarted with paste die attach(using standard dispense tools) Migrated to film die attach (with bundled dicing tape, film thickness down to 20 µ) Moving to wafer backside coated (WBC) die attach for 10 µ thickness 25
  • 26. Die Attach Film Adhesives• Die stacking is main use for film-based die attach• Need precise control of bondline thickness• Chemistry is based on epoxies and polyimides
  • 27. Flow Over Wire (FOW)• Rheological properties are modified to allow the resin to flow over and encapsulate the wires• Same base chemistries used, but formulations are optimized for proper B-stage, flow and wetting around wires
  • 28. Multiple Die Stacks Use Film Adhesive Flow Over Wire
  • 29. Polymers in a Flip Chip Package Underfill Chip Mold Compound Solder Balls Laminate Substrate• Underfills are typically epoxy-based, but some cyanate ester underfills are used for fast flow• Bismaleimide/triazine/epoxy (BT-Epoxy) is typically used for the multilayer substrates used in semiconductor packages• Epoxy and acylates are used in the soldermask used to define the pads and protect the substrate surface
  • 30. Underfill Processing • Underfill dispensed around edge of chip • Surface tension and capillary action draw resin under chip • Need tailored rheology to get fast flow • Need high filler loading for low CTE • Leads to a design challenge!Video Courtesy of Asymtek, Carlsbad, CA
  • 31. Polymers are Key Integration Enablers UnderfillsThu-Via technology- Laser friendly mold compound Graphic: Yole Development Integrated passive devices Redistribution layers (dielectrics) 31
  • 32. Mold Compound Technology• Epoxy cresol nolovak mold compounds (EMC) – Phenol novolak cured – Ease of processing, flow, molding – Good adhesion, small shrinkage – Chemical and moisture resistance• Biphenyl mold compounds – Low viscosity for wire sweep control – High filler loading – Lower moisture absorption• Multifunctional mold compounds – Mixture of biphenyl and multifunctional resins – High Tg – High filler content (rounded fused silica)
  • 33. Laminate Substrate Types• Double-sided – Typically used in wire-bonded applications – Largest volumes• Multilayer – Used for higher end packages – Required for flip-chip – High Density Interconnect (HDI) ABF substrates  Laser drilled blind via’s BT Laminate  BT Epoxy Core  Build-up layers ABF 33
  • 34. Substrate Materials• Primarily BT resin (Mitsubishi Gas Chemical) – Bismaleimide/cyanate ester (triazine)/epoxy blend• Hitachi Chemical and Mitsui – Hitachi EN 679 (high Tg epoxy based) – Mitsui BN 300 ( 300°C Tg, bismaleimide-based)• Filled PTFE composite with low Dk/Df (Rogers) – Endicott Interconnect Technologies (EIT) in volume production• Liquid Crystal Polymers – Under development, lower moisture absorption, low Dk/DF
  • 35. BT Epoxy Chemistry O O N CH2 N Bis maleimide O O O N O CH3 N C O C O C N N N Cyclo-trimerization of CH3 O bis-cyanate forming a triazine network O CH3 OH CH3 O H2 H2 H2H2C CH C O C O CH3 C C O C O C C CH2 H H CH3 CH3 n Multitude of epoxy resins enables a large formulation toolbox
  • 36. Cell Phone Camera Module Four different adhesives in a camera module: 1. Conductive die attach adhesive 2. Bonding adhesive for protective glass cover sheet (prevent damage to optical sensor chip) 3. Housing adhesive 4. Lens lock adhesive (UV cured after lens is focused during assembly)
  • 37. Summary• Polymers are key enabler in semiconductor packaging• Thermosets are extensively used – Low viscosity to enable dispensing – Fast curing with heat or light (UV) – Can be partially cured (B-staged) to enable unique film processing – Tailored to form crosslinked networks with a wide range of properties – Easy to formulate with other ingredients (silver, adhesion promoters, silica fillers, etc) – High temperature stability (lead-free reflow) – Good mechanical properties (Modulus vs. Temperature)
  • 38. Contact Info Dr. Jeff Gotro InnoCentrix, LLC 22431 Antonio Parkway Suite B160-515Rancho Santa Margarita, CA 92688 949-635-6916 (office) jgotro@innocentrix.com www.innocentrix.com

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