3D Wirebondless IGBT Module for High Power Applications Dr. Ziyang GAO Jun. 20, 2014 1 1
Outline Background Information Technology Development Trend Technical Challenges ASTRI s Solutions Concluding Remarks 2
Switchable Power (W) IGBT s Feature & Applications Power semiconductors are mainly used in the circuits of inverters/ converters for switching & converting of electricity. Unique features of IGBT modules: Wide switching frequency (1KHz 100KHz); High switching power (1KW 4MW); and Low switching power loss. 10M 1M 100K 10K 1K 100 ASTRI s focus Home Appliances Transportation IGBT Module High Power IGBT Module w/ Medium Power New Energy New Energy Motor Control Robotics & EV 100 1K 10K 100K 1M Switching Frequency (Hz) 3
Billion, USD IGBT s Application to EV & HEV IGBT: Emphasized area in the Chinese government s 12 th Five-Year Plan on Key Energy Conservation Technologies, including New Energy & New Energy Vehicles. Source: Yole, 2013 EV/HEV is expected to be the key IGBT market driver. 4
IGBT Packaging & Module Manufacturing of power module consists of 6 major steps. Back-end & packaging contribute to ~48% of IGBT module cost. 5
Outline Background Information Technology Development Trend Technical Challenges ASTRI s Solutions Concluding Remarks 6
Power Density (KW/cm2) Wafer Thickness (um) Evolution of IGBT Technologies (1/2) IGBT Wafer Development Trend 180 160 140 120 100 80 60 40 20 0 1990 1995 2000 2007 2012 2017 250 200 150 100 50 0 7
Evolution of IGBT Technologies (2/2) Flexible Foil & Sintering Ag (Semikron, 2011) Plated Cu (Siemens, 2012) Cu Lead (Honda, 2010) Leadframe (Denso, 2008) Flip Chip (Delphi, 2010) 2016 High Power & Thermal 2010 1990 s 2000 s Molded Module (Mitsubishi, 2013) Classic Design 8 SiN Baseplate (Honda, 2006) AlN Substrate (Denso, 2010) Baseplate / Heatsink (Infineon, 2010)
Outline Background Information Technology Development Trend Technical Challenges ASTRI s Solutions Concluding Remarks 9
Power Electronics v.s. Microelectronics Power electronics LED Microelectronics Power Heat Flux Density (W/cm 2 ) Reliability Product Lifetime Cooling Approaches Microelectronics 100W (Pentium 4) 100 (Pentium 4) 1.1 g-level (30 minutes) ~5 years Forced air Power 10 electronics 120KW (100A IGBT) 1,200 (100A IGBT) 20 g-level (2 hours) >10 years Liquid cool
Super High Heat Dissipation Silicone IGBT chip TIM 1 Single side cooling only! Cu pattern Substrate Cu pattern TIM 2 Company I Thermal Resistance (ºC/KW) IGBT Chip 0.6 TIM1 0.6 DBC Substrate 4.4 TIM 2 0.6 Base Plate 0.7 Module Thickness Input Power Junction Temperature 20.55 mm 0.68 MW Up to 120ºC Potential Solutions Base plate New materials (e.g., AIN substrate, nano-silver die attach, etc.); New interconnect and/or structure (e.g., wirebondless, combined baseplate & heatsink, etc.). 11
Interconnect Long-term Reliability Wire Lift-off (10x10mm 2 ) 12 Die Tilt Creep & Cracking Overshoot voltage under different interconnects
Outline Background Information Technology Development Trend Technical Challenges ASTRI s Solutions Concluding Remarks 13
Delivering Technologies: 3D Wirebondless Structure Wirebond based IGBT module ASTRI s 3D wirebondless IGBT module Design Concepts: 3D structure replacing wirebond interconnects Microstructure design on ceramic substrate for better reliability Surface treatment for enhancing surface wetting Advantages: Controllable solder-based bondline thickness SMT compatible assembly process to improve throughput Compatible to DBC substrate fabrication process 14
Reliability and Electrical Performance Module for Electrical Test Wirebond 3D-PEM Tested at China North Railway Co. Ltd. Electrical Performance 96% & 72% parasitic resistance & inductance reduction, respectively; 70% overshoot voltage reduction. Reduced 70% voltage overshoot! 15
Junction temperature ( C) Heat Dissipation Coolant in 300 250 Single side, WB-based Double side, bumped-based 200 150 Temperature contours of 3D-PEM 100 50 >35% thermal enhancement 50 100 150 200 250 300 Power dissipation (W) Comparison of junction temperatures. 16 Simulated flow patterns and temperature distributions of coolant.
HKSTP-ASTRI SiP Line Wafer Dicing Pick &Place Vacuum Reflow Stencil Print +Pick & Place Busbar Welding Reflow Underfill & Cure Front-end Back-end HKSTP-ASTRI SiP Line was ready in Aug 2013. The line has 24 major equipments to support the process developments of new packages and small volume production. 17
HKSTP-ASTRI WLP Line 18 HKSTP-ASTRI Wafer-Level-Packaging Line is under construction and will be ready by Q1 2015. The line has 12 major equipments to support the process development for TSV and other wafer level packages.
Example: UBM Fabrication for IGBT Wafers Post-wafer level processing for incoming IGBT wafers. 1200V/100A IGBT wafer with 5~8um Ni UBM 19
Concluding Remarks IGBT has been increasingly applied to many products, from home appliances, motor control, robotics, EV, new energy, to transportation. High-end IGBT module development faces many technical challenges, such as interconnect long-term reliability, module harsh environment failure, and super high heat dissipation. With the support of HKSTP-ASTRI SiP/WLP lines, ASTRI can provide one-stop total solution to local industry, including module design, process recipes, prototype samples, performance testing, and small volume pilot run. 20
End of Presentation Thank you. Suggestions are welcome! Contact us: Dr Ziyang Gao Tel: (852) 3406 2571 Email: zygao@astri.org Our corporate website: www.astri.org 21