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Evolution of international regulations and societal demand on Power Devices and Packaging Technology Emanuele Scrofani Package Engineering & Development IMS B-E Technologies Department STMicroelectronics Graz, 2012 June 14th

Key Topics of Presentation

• Key Parameters & Factors for Power Devices • Evolution of Power Packaging technologies: • High Density & Key Advanced axes

• High Integration vs. Energy Saving & High Efficiency • Environmental & Human Health and Sustainability Regulations

• Conclusion




• Conclusion

Key Parameters for Power Devices S -

G +

• Generated Power  Pg = Ron * I^2 + Funct (f.cy) • Dissipable Power  Pd= (Tj – Tc) / Rthj-c Pd >= Pg  Minimum Ron, Minimum Rth D+

Key Factors for Power Dice • Low Ron • Low Thickness • Hi Temp, Hi Speed

PMOS example

Key Factors for Power Packaging • Interconnections • Die Attach • Materials

Minimum Losses, High Efficiency




• Conclusion


• Key Parameters & Factors for Power Devices • Evolution of Power Packaging technologies: • High Density & Key Advanced activities


• Conclusion

Power Packaging Evolution

∙ Die Attach (Hi Conductivity) ∙ Hi Temp & Speed (SiC & GaN) ∙ Ultra thin dice (till 40um) ∙ Dual side Cooling ∙ Interconnections (clip, ribbon, ..) ∙ ..

DENSITY

POWER

Hi Power Density, Hi Efficiency, Hi Reliability Lead free & Hi Reliability Die Attach

High Temperature & Frequency

Advanced Die Attach:

   

 Ag paste  Ag sintering  AuSn, CuSn diffusion soldering

Miniaturization (SiC & GaN) Molding Compound Sawing, Bonding Processes Materials

Ultra thin dice: 110 um  80 um  60 um 40 um

Dual Side Cooling:

New Process, F/E-B/E compatibility:

 

   

Improved thermal performances Improved silicon life time

Till -50% Rth, -20% Ron from 280um Dedicated F/E-B/E process flow Improve dice robustness Improve wafers/dice handling (from KGD to W/B)

Hi Reliability Interconnections:  Al/Cu Cu Thermal Expansion Coefficient closer to silicon -> Stress on the silicon dice is minimized  Copper on Copper Improved Robustness and Reliability -> heavy Copper wire (or ribbon) on heavy Copper front metallization

Al/Cu ribbon

Copper on Copper

Dual Side Cooling Approaches

Best thermal performances (1/20 RthJ-Top Case for PowerFLAT 5x6) Higher current carrying capability Low operating temperature and longer life time

Rth improvement: Dissipation by Top

Power Interconnection Technology Evolution

Heavy & Multiple Wires

Clip Ribbon

Thin Wires

Advanced Interconnection Technologies From wires to ribbons – the benefits: • Lower mechanical stress on the silicon

Ribbon Automotive grade Bonding Technology !

• Higher current capability due to larger equivalent bonded area • Improved RDS(on) due to the lower contact resistance • Same process (ultrasonic wire bonding) and materials (Al 99.99) • Comparable benefits vs. copper CLIP but more reliable process • Higher Productivity vs. multi wires (+ 75% avg UPH) • No additional silicon process steps • Better Yield & Quality

Strong Reliability improvement: Al-Cu (5 x Life time Al) •Cu thermal expansion coefficient closer to silicon •Less stress on the silicon by Al softness •Already tested by ST in 2008 in PSO-10 Copper on Copper (10 x Life time Al) •More robust joint vs. reliability •Heavy Copper ribbon or wire on heavy Copper front metallization and L/F

Cu on Cu

Al/Cu


∙ Die Attach (Hi Conductivity) ∙ Hi Temp & Speed (SiC & GaN) ∙ Ultra thin dice (till 40um) ∙ Dual side Cooling ∙ Interconnections (clip, ribbon, ..) ∙..

DENSITY

INTEGRATION ∙ Power FLAT & Multi-Island ∙ Intelligent Power Module ∙ Hi End Power Module

POWER

Power Discrete Packaging Evolution vs. PFLAT, DSC & Multi Islands, Hi Temp X2Pak H.C. 2,3,6,7 L

ClipPAK

PFLAT 5x6 & 8x8 Dual Side Cooling

DPak H.C. 2,3 L

PolarPAK PQFN 3.3x3.3 Wire & Ribbon

I2packFP SO-8 RIBBON

TO220/D2PAK Cold by pass

PFLAT 2x2

PSO-36 PSO-10 RIBBON PQFN 5x6 Wire & Ribbon

PowerFLAT8x8 HV

OctaPack

Hi Temperature & Frequency (SiC & GaN) PFLAT 3.3x3.3 HV

PowerFLAT 5x6 Ribbon & Clip with 1,2 Islands PFLAT Triple Island

Chip on Chip SO-8 CLIP

Bond / Mold Less

PFLAT 5x5 & 5x6 HV

PowerFLAT applications Foot print reduction vs. D2pak & Dpak Power Packages

Computer, Telecom, Consumer & SMPS, Automotive, Mobile phone charger, USB adapter, Lighting & Health Care, Solar, Telecom Power, ..

Less societal impact

Intelligent Power Modules Energy Saving, Global Foot Print Reduction

Application:

Motors drivers (Air-condition, Refrigerator, Washing machine, .. Advanced Home Appliance )

Purpose:

To replace traditional Customer PCB with many components by 1 System In Package

Benefits:

Save Energy (30-40%) by drive integration, Global foot print reduction, Save cost for the whole supply chain, Performance optimization by customized design

Complexity:

Up to 40 process steps, Integrated in 1 System In Package till 20-25 dies from different types (up to 6-8), Au Wires + Al Wires, with DBC, with PCB + SMD for 10-30 components

Less societal impact

Intelligent Power Module

Leadframe (Copper)

Glue (Epoxy base – Ag)

Au wire bonding (Au)

PCB

Al wire bonding (Al)

Drivers ( Silicon )

Solder (Sn-Ag)

DBC (Cu – Al2O3 – Cu) IGBT's – Diodes (Silicon)

Molding compound ( Epoxy ) Plating (Sn)

Hi End Power Module: Premise Kyoto Protocol: -30% of CO2 emission by 2030 Hybrid, Electrical Vehicles, ..

126$

Lighting 21%

54% of WW energy consumption at 2030 can Oil price increase be saved by Energy Efficiency Increase:

30% only for Motor Control

> 85% of produced energy comes from hydrocarbures Photovoltaic, Eolic, …

Motor Control 55%

Energy Consumption Repartition

Power Supply 24%

Hi End Power Module: Hi Efficiency, New Energies • The field of Energy and Energy Saving has a key role due to the high impact of Power Electronic Conversion efficiency in all energy consumption scenarios • Key aspects are the Generation, Transformation and Use of the Energy • GaN and SiC technologies, with intrinsic lower losses and ability of operating at high frequency and high temperature, allow higher efficiency, reduced system size and reduction of the auxiliary cooling system • Emerging application domains: Sustainable Mobility (Hybrid & Electrical Vehicules) Industrial Automation, Robotics, Aeronautic, .. New Energies Generation & Conversion (photovoltaic, eolic, .. )

• Key Packaging solution: Hi End Power Module, using SiC & GaN technologies and advanced IGBT & PMOS, with High level of integration, operating at Hi Current & Hi Temperature

Chain value: from Silicon to Application Processes Devices Substrates

SiC & GaN Devices Advanced IGBT

Hi Current (> 50A) & High Temperature (>200 °C) Power Module

Power Module integration inside Application

Hi End Power Module

STA3 Module

STA1 Module

Power Module Evolution 

Heavy Copper and/or Bondless technology



Sintering and/or Diffusion soldering for Die-DBC, DBC-Base Plate, Die-Copper foil for heavy Copper, .. High Reliability



I/O interconnection (Co-molded Pins, Ultrasonic Welding process)



High Temperature (>= 200°C) & Automotive grade (case & whole system), .. High Reliability



Base plate (Flat, Pin fins, AlSiC bulk, Cu bulk with sintering)



Thermal Interface Material (pre-applied solid grease, graphene , ..)



Dual Side Cooling Typical structure

Plastic case

2

Embedded Pin Insulating substrates • IMS (Al, Cu) • DBC / AMB (Al2O3, AlN, Si3N4) • Integrated substrates (embedded heat sink)

Plastic Lid

Base Plate • Copper • AlSiC (Flat) • AlSiC (with pin fins)

Ultrasonic Welding Pin

Wires

Dice Presentation Title

12/04/2012

Potting material • Low stress, Thermal conductive


∙ Die Attach (Hi Conductivity) ∙ Hi Temp & Speed (SiC & GaN) ∙ Ultra thin dice (till 40um) ∙ Dual side Cooling ∙ Interconnections (clip, ribbon, ..) ∙ ..

DENSITY

∙ RoHS ∙ Ecopack ∙ Ecodesign ∙ EMI/EMC ∙ ..

INTEGRATION ∙ Power FLAT & Multi-Island ∙ Intelligent Power Module ∙ Hi End Power Module

POWER

ENVIRONMENT & HUMAN HEALTH

∙ Lead free plating / dipping ∙ Green molding compound ∙ Leadfree solder die attach ∙ Electromagn. compatibility

SUSTAINIBILITY REGULATIONS

Standards, Regulations, Requirements about substances restrictions • International organizations, Countries and Customers have started during last 15-20 years to restrict the use of some hazardous substances that may adversely affect human health or the environment:

• The EU RoHS Directive restricts the use of 6 hazardous substances in all new Electrical and Electronic Equipments (EEE) • The China RoHS Directive establishes a regulatory framework for substance restrictions, pre-market certifications, labeling, and information disclosure • IEC 61249-2-21 and JPCA-ES-01 standards limit the use of halogenated compounds • RoHS: Restriction of the use of certain Hazardous Substances

ST very sensitive from beginning

EU and China ROHS Directive Limits for Banned Substances • The European Union RoHS Directive 2002/95/EC, revised in June 2011 as Directive 2011/65/EC, defines the maximum limit of some impurities in homogeneous materials of electronic packages (Heavy metals and Brominated compounds): • • • • • •

Lead (Pb, 0.1 %) Mercury (Hg, 0.1 %) Cadmium (Cd, 0.01 %) Hexavalent chromium (Cr-VI, 0.1 %) Polybrominated biphenyls (PBB, 0.1 %) Polybrominated diphenyl ethers (PBDE, 0.1 %)

Restricted Substances & Exceptions update is expected not before July 2014

• The China RoHS Directive requires the disclosure of the same 6 EU RoHS hazardous substances, with same maximum concentrations, by Labeling of product and packaging

IEC 61249-2-21 and JPCA-ES-01 "Halogene-Free" requirements • The Halogens are a chemical series, elements in Group 17 of the periodic table: fluorine, chlorine, bromine, iodine and astatine • The purpose of these requirements is to ensure a high level of protection of human health and the environment vs. Halogens and Antimony oxide • For suspect substances, a chemical safety assessment must be performed and shall include the following steps:

• • • • •

Human health hazard assessment Physic-chemical hazard assessment Environmental hazard assessment Persistent, Bio-accumulative and Toxic (PBT) assessment Very Persistent and Very Bio-accumulative (VPVB) assessment

"Halogene" contents requirements • RoHS : bans 2 Halogenated flame retardants families (PBB & PBDE)

• JAPAN JPCA-ES-01 :

• IEC 61249-2-21 :

Br + Cl < 900 ppm

Br < 900ppm Cl < 900 ppm Sum of Halogens < 1500ppm (for PC boards)

• JEDEC JIG 101 : • To declare when more than 1000ppm of Brominated compound • To declare when more 1000ppm of Sb2O3

REACh regulation Chemicals Risks Management Global regulation Diversity and Equal Opportunities REACh (Registration, Evaluation and Authorisation of Chemicals), into force from Employee Health, Safety & Well-being June 1st 2007, aims to regulate the use of chemical substances within the European Union, Labor Rights and Socialcontents Issues of our finished products, imposing legal duties on chemical impacting on chemical manufacturers and importers, on chemical downstream users and on articles manufacturers and importers:

• All chemicals need Registration to be used • All Restrictions of uses are legally binding • Upon Authorization a total phase out of chemicals is requested

• Substances of Very High Concern need to be declared if present in articles • Regulation is periodically updated and, since early 2008, 7 lists of so called candidate Substances of Very High Concern were issued for a total of 73 substances

ST well involved from beginning for proposal lists via the ESIA (European Semiconductor Industry Association)

ECOPACK Trade Mark

• ECOPACK is a registered trade mark ST has strongly contributed to establish that defines environmental friendly components through specific requirements for materials and manufacturing processes: • ECOPACK1 = RoHS compliance, Lead (Pb) removed from Dipping / Plating (SnPb to Sn), still exception for Die Attach material • ECOPACK2 = ECOPACK1 + removal of Brominated, Chlorinated and Antimony oxide flame retardants (Br+Cl< 900ppm and Sb