4 August, 2015
Agenda Motivation: Environmental and health endangerment of lead Situation: Lead & the use in Electronics Status on legislation DA5 Structure and Project: 2 Cooperations and partners Requirements, Applications and Approaches for possible solutions Results Timeline and Conclusion 4 August, 2015
Sustainability Efforts Bosch: Just about half of Bosch’s 2014 research and development budget (4.9 billion euros) focused on the environment and on products designed to conserve resources. It is here that the challenge of the next century lies. Our objective: to develop innovative, useful, and exciting products and solutions to enhance quality of life – technology that is “Invented for life.” Infineon: We understand sustainability as the symbiosis between economy, ecology and social engagement.
Examples for Environmental Protection Powertrain CRI Innovative electro-tools with Li-Ion technology Photovoltaic Saving energy in basestations Wind energy (gears) ESP Power plant 4 Household/Office Solar thermal Smart grid Energy efficient appliances More efficient SSL lighting 4 August, 2015
Lead: Environmental and Health Endangerment Environmental dangers Health dangers: 5 Poisonous substance Neurotoxin Accumulates in soft tissues & bones Damage to nervous system Causes brain disorder Causes blood disorder in mammals 4 August, 2015
Agenda Motivation: Environmental and health endangerment of lead Situation: Lead & the use in Electronics Status on legislation DA5 Structure and Project: 6 Cooperations and partners Requirements, Applications and Approaches for possible solutions Results Timeline and Conclusion 4 August, 2015
Use of Lead in Electronics Expiry / Review Date Exemption Lead in soldering on PCB, the components and their finishes E/2015 Lead in solder for other application, not on PCB or glass E2010 Lead in finishes of Al-Capacitors E/2012 example IC packages Lead in soldering on glass for mass-flow sensors 2 E/2014 Lead in high temperature melting solders Review 2019 Lead in compliant pin connector systems Review 2019 FlipChip Lead in solder between die and carrier in flip chip packages Review 2019
Use of Lead in Electronics Use of Lead containing Solders in PCB PbSn63 or PbSn62Ag2 are & have been used for soldering components onto a printed circuit board (PCB) Leadfree alternative solders known & implemented E.g. SnAg3.8Cu0.7 (SAC) Use of high Lead containing Solders as chipsolders in packages PbSn5 or PbSn2Ag2.
Materials for Die Attach: Solder Alloys Melting Melting temperature temperature of solder alloys 400 400 Temperature °C in °C Temperature in 350 350 Tem perature load ( d ur ing sub seq uent assemb ly p r o cesses & p cb - so ld er ing ) 300 300 250 250 200 200 150 150 In 48 Sn B i4 2S n IInn3 3A Sn A gg 36 P b2 Ag Sn 9Z n Sn 3 Sn .5 A 25 g A g1 0S b Sn 5S b Sn 8S b P b1 9I n A u2 Pb 0S n 5S n2 .5 Pb Ag 2S n2 .5 Ag P Pb b5S n 1S n1 .
Materials for Die Attach: Solder Alloys Melting Melting temperature temperature of of solder solder alloys 400 400 Temperature in °C 350 350 Tem perature load ( d ur ing sub seq uent assemb ly p r o cesses & p cb - so ld er ing ) 300 300 250 250 200 200 150 150 IInn4 488 SSnn B B ii442 2SS nn IInn3 3A Sn A gg 36 P b2 A g S n9 Zn Sn 3 .5 Sn A n2 g 55A Ag g11 00SS bb SSnn 55SS b Sn 8S b Pb 19 In A u2 0 Pb 5S Sn n2 .5 Pb 2S Ag n2 .5 Ag Pb 5S Pb n 1S n1 .
Materials for Die Attach: Solder Alloys Melting Melting temperature temperature of of solder solder alloys 400 400 Temperature °C in °C Temperature in 350 350 Tem perature load & lead-free Tem perature load ( d ur ing sub seq uent assemb ly p r o cesses & p cb - so ld er ing ) 300 300 250 250 200 200 150 150 IInn4 488 SSnn B B ii442 2SS nn IInn3 3A Sn A gg 36 P b2 A g S n9 Zn Sn 3 SSn .5 A n22 g 55A Ag g11 00S Sb b SSnn 55SS b Sn 8S b Pb 19 In A u Pb 20S n 5S n2 .5 Pb 2S Ag n2 .5 Ag P Pb b5S n 1S n1 .
Agenda Motivation: Environmental and health endangerment of lead Situation: Lead & the use in Electronics Status on legislation DA5 Structure and Project: 12 Cooperations and partners Requirements, Applications and Approaches for possible solutions Results Timeline and Conclusion 4 August, 2015
Legislation European End-of-Life Vehicle (ELV) Directive (2000/53/EG) mandates conversion to environmentally friendly materials Annex II (2010/115/EU, exemptions 8e-j/10d) ELV Rev.7 Exemption may be cancelled if an alternative is available and proven For 8e (lead in HMT solder) revision 7 started in Sept.
Agenda Motivation: Environmental and health endangerment of lead Situation: Lead & the use in Electronics Status on legislation DA5 Structure and Project: 14 Cooperations and partners Requirements, Applications and Approaches for possible solutions Results Timeline and Conclusion 4 August, 2015
DA5 Project Decision to form DA5 consortium in 04/2009 DA5 focus on the use of high melting solder in semiconductor applications, especially for die attach in power packages. Other applications covered in ELV Annex2, exemption 8e are out of DA5 scope and might have other requirements.
DA5 Approach Press Release (Q2/2010) Bosch (Division Automotive Electronics), Freescale Semiconductor, Infineon Technologies, NXP Semiconductors and STMicroelectronics today announced that they have formed a consortium to jointly investigate and standardize the acceptance of alternatives for high-lead solder for attaching die to semiconductor packages during manufacturing. The five company consortium is known as the DA5 (Die-Attach 5).
DA5 Project Objectives Joint development of semiconductor suppliers to address and mutually define the direction of Pb-free solder d/a-technology development DA5 is working together with suppliers to find feasible alternative solutions for lead-free die-attach Evaluate available and potential alternatives Prioritize drop-in solutions Suppliers are encouraged to approach DA5 with their solutions Identification of sustainable, enduring, standardized, reliable and dependable solutions for
DA5 Setup for Pb-free Power Die Attach DA5 Major material suppliers from Europe, US and Asia were assessed 15 Preferred material suppliers were identified 7 Selected material suppliers out of 15 were chosen 18 Continuous contact is established.
Targeted Applications Power Modules Smart Power ASICs Power MOS-FETs & IGBTs in SMD packages Power MOS-FETs & IGBTs in Through-Hole packages (THT) Different applications have different specifications and may require different leadfree solutions 19 Pictures not to scale 4 August, 2015
Reliability Requirements * AEC-Q100/-Q101 Grade 0 Typical Tjunction 175°C; max. up to 200°C Thermal/electrical properties Improvement compared to existing solutions needed Reflow 260°C (SMD) Moisture sensitivity level MSL3 or better (SMD) Wire bonding temp. up to 260°C Physics of failure understood The full specification document “DA5 Pb-Free Die-Attach Material Requirements” is available upon request at DA5 (contact last page).
Materials 4 different material “classes” are in discussion DA 5 21 4 August, 2015
Conductive Adhesives I Principle High electrical and thermal conductivity of adhesives is achieved by increasing silver filler content and very dense packing of filler particles. Reduction of particle size to micro and nano scale stimulates a sintering of the silver particles during the resin cure process. The remaining resin content is a key factor determining the physical properties of the material.
Conductive Adhesives II Advantages Good adhesion to different types of chip backside metals and leadframe platings. Good thermal and electrical performance. Common production methods and equipment can be used for the application of the material and placement of the chip (Drop-In Solution) Box oven curing in Nitrogen atmosphere with standard equipment. Pass automotive environment stress test conditions (AEC-Q100, AEC-Q101).
Conductive Adhesives III Limitations Some highly filled adhesives contain solvents to improve rheology. This requires more careful handling and control of the manufacturing process. It also bears a risk of leadframe and die surface contamination. Material cost is higher compared to standard adhesives and solder alloy. Process window depends on die size with maximum die sizes up to 8x8mm². Application is limited to low and medium power devices and maximum moisture sensitivity level MSL3/260°C.
Ag Sintering I – Overview Principle Advantages No self-alignment as with solder wetting nm-scale Ag particles are at risk of being banned New concept in molded packaging - no prior knowledge of feasibility, reliability or physics of failure Production equipment changes might be needed (low-O2 ovens?) Elevated risks 25 Fulfills many of the drop-in replacement requirements for a paste Better thermal and electrical performance than Pb-solder possible Disadvantages Ag-
Ag Sintering II – Assembly Dispensability and staging time are improving, but issues persist Voiding is improving Process control issue: C-SAM scans are difficult to interpret Bond line density differences and unsintered material should be improved 26 Die edge Die center Unsintered Agparticles are improving 4 August, 2015
Ag Sintering III – 0-hr & Reliability Results Oxidation and/or delamination of interfaces is common, even at 0-hr, lowering adhesion and electrical & thermal performance.
TLPS materials I Advantages Disadvantages Medium metal content in die attach Medium space rate, filled with Epoxy New concept in molded packaging - no prior knowledge of feasibility or reliability Only suitable for medium dies < 24 mm2 Potential compatibility issue with Cu leadframes Elevated risks Principle 28 Fulfills many of the drop-in replacement requirements for a paste Better cost position compared to Ag sintering solutions Good electrical performance on Ag-plate
TLPS material II The hybrid material showed a medium space rate. The spaces are filled with epoxy material The reflow process is very critical and has to be further optimized, the reflow profile seems to be product specific Reliability results are contradictory. Results are package / leadframe material dependent.
Alternative Solders I Properties to be considered 30 Robust manufacturing process Repeatable solder application Stable wetting angle Surface compatibility (chip backside, lf finish) Zn based alloy reference Reliability Voiding / cracking / disruption after stress Growth of brittle intermetallics at high temperature Disruption during temperature cycling 4 August, 2015
Alternative Solders II Zn-based Alloys Bi-based Alloys Low thermal conductivity & low melting point Performance minor to high lead solder no replacement option SnSb-based Alloys 31 New formulations demonstrate lower mechanical stress and reduced die cracking Growth of brittle intermetallics at high temperature limits reliability Improved reliability expected for die<10mm^2 in combination with a new experimental lf surface Risk of Zn re-deposition can only be falsifi
Key Performance Indicators I Comparison of competing Technologies DA5 assessment refers to best tested material in class 32 4 August, 2015
Key Performance Indicators II Comparison of competing Technologies DA5 assessment refers to best tested material in class 33 4 August, 2015
Key Performance Indicators III Comparison of competing Technologies DA5 assessment refers to best tested material in class 34 4 August, 2015
Key Performance Indicators IV Comparison of competing Technologies DA5 assessment refers to best tested material in class 35 4 August, 2015
Agenda Motivation: Environmental and health endangerment of lead Situation: Lead & the use in Electronics Status on legislation DA5 Structure and Project: 36 Cooperations and partners Requirements, Applications and Approaches for possible solutions Results Timeline and Conclusion 4 August, 2015
DA5 Timeline (Overview/Milestones) 12th F2F Neubiberg Technology review & Supplier feedback 2ndF2F Reutlingen 1st F2F Sibiu General project activities 3rd F2F 4th F2F 9th F2F 10th F2F 11th F2F 5th F2F 6th F2F 7th F2F 8th F2F Agrate Regensburg Munich Munich Nijmegen Reutlingen Agrate Regensburg Munich start of cooperation Q1 Q2 NDA signature Q3 2009 Q4 Press release Q1 Q2 Report Dr. Deubzer Reports Dr. Deubzer conf.
Substitute Material(s) for High-LeadProcess(ELV) Solders DA5 - Automotive Release Package Semiconductor Component Electronic Control Unit Vehicle Lead-free Die Attach Material Lead-free Package Technology Lead-free Component Lead-free ECU Lead-free Vehicle Material freeze Technology chain DA Material Technology Prototype Supply DA5 scope DA Material Assessment Physics of failure Workability, Reliability Manufacturability 38 typ. 2 years type release Development Material Supplier typ.
Substitute Material(s) for High-Lead Solders DA5 - Industrial Release Process(RoHS) Package Semiconductor Component Lead-free Die Attach Material Lead-free Package Technology Lead-free Component Material freeze Technology chain DA Material Technology Prototype Supply DA5 scope DA Material Assessment Physics of failure 39 typ. 1 ½ years type release Development Workability, Reliability Manufacturability Material Supplier Lead-free Product Package Development Supply chain typ.
Conclusion Today’s lead-free material technologies for semiconductor applications (die attach) are not ready to substitute high-lead solders in power applications Substantial development efforts have been running for 6 years now and will be continued.
Contact Information Speaker of the DA5 consortium: Bodo Eilken Infineon Technologies AG Email: bodo.eilken@infineon.com DA5 customer presentation: http://www.infineon.com/dgdl/DA5_customer_presentation.
