Leistungselektronik in der Leiterplatte Andreas Ostmann Fraunhofer IZM Gustav-Meyer-Allee 25, 13355 Berlin, Germany email: 10. AT&S Technologieforum 9. - 10. Oktober 2013, Graz
Inhalt Einleitung Einbettung von Leistungselektronik Heutige Produkte Forschungs- und Entwicklungsprojekte Ausblick und Zusammenfassung
Interconnect Evolution First level chip interconnection technologies inside a package: chip & wire flip chip chip embedding established smallest in 2D smallest in 3D
Chip Embedding Advantages & Challenges via to substrate via to chip chip dielectric core substrate adhesive Advantages thin planar packaging, enabling 3D stacking improved electrical performance by low inductances high reliability by direct Cu to chip interconnects cost saving by large area process Challenges improvement of process yield demonstration of reliability for automotive and high power new supply chain structure under formation
Chip Embedding - Technology Evolution Chip Embedding in organic substrates use of PCB technology & material Production started Europe Asia First Patent Basic R&D Production Demos Production 1968 2000 2005 2013
Chip Embedding Production Format Comparison Manufacturing on leadframes Fan-out wafer-level package Chip embedding in substrates 24 x24 18 x24 12 8 8 ~ 24 sqin ~ 50 sqin ~ 113 sqin ~ 432 sqin ~ 576 sqin dominating technology many process options cost optimised OSAT thin film technology fast production ramp-up today high I/O chips 3D under development OSAT PCB technology begin of production today low I/O chips intrinsic 3D and power capability PCB manufacturers
Chip Embedding Patents Distribution of Publication countries 721 patents were filed from 1967 to 2012 70% of patents were filed since 2006
Chip Embedding Current Production & Forecast today 338 Munits/year
Power Chip Packaging Switching power converters have a large field of applications: from mobile phones (some W); over cars (several kw) to large solar and wind energy farms (some MW) Power Packages single chip packages for MOSFETs, IGBTs or diodes use in lower power applications Power Modules use for mid and high power applications include e. g. IGBTs and diodes in half bridge configuration electrical isolation to backside
Motivation of Power Embedding Established Power Modules power chips soldered to DCB substrate top side connection by heavy Al wire bonds Issues high inductance of wires too high for fast switching SiC and GaN chips lifetime limitation by bond wire reliability
Motivation & Concept Current module construction requires height for vertical interconnection Current modules offer two interconnect levels only: DCB and wire bond. This restricts the design freedom Manufacturing is on single module level, not by an efficient large area process There seems to be room for improvement! replacement of bond wires by plated thick Cu connections Al wire bonded IGBT on DCB embedded MOSFET
Power Chip Embedding - Features Embedding of power chips into Printed Circuit Board structures cost saving by large area process (600 mm panels) Direct connection by Cu conductors / no bond wires multiple wiring layers possible shielding capability high reliability by direct Cu to chip interconnects Completely planar conductors over embedded chips SMD assembly on top allows driver integration top side cooling possible
Power Chip Embedding Special Requirements Power Components MOSFET,s IGBTs, Thyristors, Diodes Due to resistivity of Si only a vertical flow of high currents is possible power components have contacts on bottom and top of the chip source gate example: MOSFET chip drain typical values chip area 1 100 mm² chip thickness 50 400 µm voltages up to 1200 V currents up to 100 A top side contacts Al standard for Al wire bonding, not compatible to embedding Ag for soldering on large dies, use for embedding under investigation Cu for Cu wire bonding, fully compatible to embedding eless NiPd low cost metallisation, use for embedding under investigation back side contact Ag standard for die attach (solder or adhesive), use for embedding under investigation Cu already partially available, fully compatible to embedding
Power Chip Embedding Manufacturing Process conductive chip attach topside contact by laser drilling and Cu plating 5 µm Cu bumps required backside contact by conductive die bond adhesive, soldering, sintering very good thermal conductivity die attach on thick Cu possible compatible to standard Ag backside embedding by lamination via drilling top, through-via Cu plating and structuring Ag sintered die bond
Embedding Process Equipment Panel format 610 x 456 mm² Die attach (Datacon evo/siplace CA3) Embedding (Lauffer) by RCC lamination (5 µm Cu, 90 µm dielectric) UV laser drilling (Siemens Microbeam) of microvias / mechanical drilling (Schmoll MX1 Cu electroplating / via filling (Ramgraber automatic plating line) Dry film resist application Laser Direct Imaging (Orbotech Paragon 9000) of circuitry pattern Subtractive Cu etching (Schmid) Electrical test (Spea flying probe tester)
Power Chip Embedding Product Types MOSFET Power Package single chip package low thermal & electrical resistance products available MOSFET driver Power System-in-Package (SiP) more chips in one package low thermal & electrical resistance products available R IGBT logic IC C IGBT High Power Module electrical isolation to cooler multiple wiring layers integration of driver / controller R&D activities
Products Today Power and Logic The production of embedded packages is ramping up fast Today 2013: 340 Mio., Forecast 2016; 1700 Mio. (source Yole) Smart Phone Market DC/DC converters Power management units Connectivity module Computer market MOSFET packages Driver MOS SiPs PCB Embedding Technology is implemented or will come soon at PCB manufacturers Semiconductor manufacturers OSATS
Products DC/DC Converter SiPs 650 ma DC/DC converter System-in-Package with embedded chip volume manufacturing manufactured by manufactured by
Products Power Chip Packages & SiPs small SMD power package embedded MOSFET / Driver MOS manufacturing on PCB format reliability qualification fully passed SMD package with embedded MOSFET MOSFET SMD package with 2 embedded MOSFETs & driver schematic of package with embedded MOSFET Licensing and process transfer from Fraunhofer IZM
Production Power Chip Package
Embedded Power Modules traditional power module Gate Al 2 O 3 MOSFET Drain Source Heat sink embeding on PCB substrate embeding on ceramic substrate FR4 MOSFET MOSFET thick Cu Al 2 O 3 or AlN Heat sink production panel 610x456 mm² (18 x24 ) isolation and thermal conduction by high- laminate low to medium power modules Heat sink production panel 125x175 mm² (5 x7 ) isolation and thermal conduction by Al 2 O 3 or AlN DCB high power modules
Project HERMES Project goal industrialization of Embedding Technology Realization of an embedded Intelligent Power system Operation at 600 V / 8-22 A Current product: - IGBTs on wire-bonded on DCB - logic SMDs on small PCB - leadframe based and overmolded Embedding of power devices (IGBTs) into PCB Replacement of DCB, leadframe and overmold SMD assembly of application-specific logic devices and passives on top Infineon CIPOS module
Project HI-LEVEL 50 kw Power Inverter Development of planar power modules for 50 klw motor inverter Features Reduction of height by 10 mm Cost efficient production without expensive packaging Integration of control electronics Capability for double-side (water) cooling
Project HI-LEVEL Electrical Topology 10 kw test module single phase, 20 660 V AC 2 IGBTs 200 A 2 freewheeling diodes DC link < 10 nh expected 50 kw demonstrator module single phase, 20 660 V AC 6 IGBTs 200 A 6 freewheeling diodes DC link < 30 nh expected Parasitic stray inductance L s can be significantly reduced by embedding reduced overvoltages during turn-off of each IGBT faster switching reduced switching losses
Project HI-LEVEL Packaging Construction Cu pad metallization laser-drilled and Cu-filled micro-via IGBT IGBT 400 µm Cu Ag sintered high Tg (185 C) die bond dielectric high dielectric (2 W/mK) Topics of current investigations pressure-less / low-pressure sintering on large panels application of 5 µm Cu bumps on thin IGBT wafers high voltage isolation of thermally conductive dielectric
Project HI-LEVEL Layout 10 kw Test Module
Project HI-LEVEL Status 10 kw Test Module 400 µm Cu on thermal laminate substrate. Die bonding on sinter paste. first modules finished electrical evaluation ongoing improvements required for die sintering to be done long-term stress tests (passive) active power cycle tests Microvias on top of IGBT
Project HI-LEVEL First Test 10 kw Evaluation Module successful test of switching (double pulse switching) @ 250 V 770 A (on) / 970 A (off) @ 400 V 500 A (on / off)
Project HI-LEVEL Layout 50 kw Demonstrator Module Conventional module (in production)
ECPE Project Ultra Low Inductance Package for SiC Best Paper of PCIM 2013 Conference Current measurement DCB DC - JFE T Diode Gates DC link capacitors Out DC+ Full bus bar structure using PCB Process on a DBC DC capacitors on the module DC link current measurement included Abb. 1: Explosionsansicht des Modulaufbaus Package sets new benchmark: ultra-low DC-link inductance
ECPE Project Ultra Low Inductance Package for SiC Switch off at 20 A: Voltage slope 19 V/ns current slope max. 4 A/ns (50% to 90%) Low overshot (approx. 10 V) very little ringing (frequency 240 MHz) DC-link inductance of 0.8 nh
Power Embedding Production and R&D 10000 1000 1 MW R&D and Customer Projects Current (A) 100 10 Blade Packages Reihe1 Production Reihe2 R&D Si Reihe3 R&D SiC 1 DC/DC converter SiPs 0,1 1 10 100 1000 10000 Voltage (V)
Future Perspective First a Look Back... first vacuum tube diode 1908 first transistor 1947 first integrated circuits 1961 Si wafers up to 300 mm Eelectronics Era Semicond. Era Moore s Law Era single device manufacturing highly parallel manufacturing introduction of planar semiconductor technology initiated Moore s Law Era
Future Perspective Power Electronics Packaging IGBT IGBT wire-bonded power chips on DCB Traditional Power modules planar module with embedded power chips Planar Power Packaging single module manufacturing large panel manufacturing low inductance high heat transfer high integration level high productivity
Conclusions The embedding of power components offers new opportunities in terms of integration, cost and electromagnetic performance It is an emerging technology where not all questions are solved up to now It relies on existing manufacturing processes and can even be combined with ceramic substrates for high power applications Open topics: Reliability and lifetime for higher power, thermally conducting safety isolation but: embedding technology offers one solution for many different types of power applications by using the same manufacturing line R logic IC C MOSFET MOSFET controller IGBT IGBT