LED Packaging Innovations for Smart Lighting Systems

Transcription

1 Outline LED Packaging Innovations for Smart Lighting Systems James J.-Q. Lu Rensselaer Polytechnic Institute (RPI), Troy, NY, USA Introduction to Smart Lighting LED Packaging Challenges Advances in LED Packaging Summary 2 OVERVIEW of RPI Smart Lighting ERC Robert F. Karlicek Director, Smart Lighting ERC Professor, ECSE at Rensselaer 34 Faculty members 36 Full time graduate students 25 Industrial member companies Core Partners: Another Revolution in Lighting is Coming First Wave 10 year, ~$35M commitment from NSF Additional funding from Empire State Development/NYSTAR as well as industrial members Educational Outreach Partners: Signs of Bulb/Socket Extinction underway Disruption in Lighting Technologies and Businesses 3 Growing Industry Interest in Lighting Based Services 4

2 Another Revolution in Lighting is Coming Second Wave RPI Smart Lighting ERC Vision Synthesizing Light for the Benefit of Humanity Engineered Light for Energy Efficiency, Health, Veldvest Primary School BASF Smart Building Interfaces Smart Grid Interfaces Healthcare System Interfaces Smart Lighting 5 6 The Second Wave: Smart Lighting New Lighting Capabilities and Features Illumination providing Data Illumination providing Video Illumination for Health & Safety Illumination Systems that Think The Not just Right Smart Light Thinking Where about and Lighting When You Systems, Need but It Smart Lighting Systems that Think! Smart Lighting ERC Strategic Plan Center Goal 1 Energy Savings at 2X the current DOE roadmap for Solid State Lighting NSF 3 Plane Diagram Level 3 Systems Level 2 Enabling Technology Level 1 Basic Science Engineered System 1 Adaptive Lighting Testbed High Performance Sources New LED devices Advanced Drivers Opto-electronic Integration Center Goal 2 Reduce Health Care Costs by 10% with Smart Lighting Industry Involvement Integration Center Goal 3 Use Smart Lighting to improve Workplace productivity by 10% Engineered System 2 Communications Testbed Adaptive Control and Communications Research Luminaire Integration Sensor Subsystem Transceiver Subsystem Full Function Light Sensors Plasmonic enhancement High speed directional detection Integrated sensor circuit design 7 8

3 Roadmap Long Term Realization Integration of control, communication, human health Basic LED Chip Styles Sapphire Adaptive Lighting System Visible Light Communications Intuitive User Interface Integration with Entertainment Cost Effective, Efficient and Reliable LED Fixtures Distributed Sensors: Pixelated Room Building, Grid Interface Biochemical Detection & Mitigation Personalized Circadian Rhythm Regulation Lateral Vertical Chip Flipped Chip Low Power (Typically < 0.5W) Volumetric Emitter Most Established Design Display, indicator, signage, other High Power (1W to > 50W) Surface Emitter Best Power Performance Lighting and Projection Applications High Power (1W to 10W) Pattern depends on Sapphire Removal Most Flexible Design for LED Arrays Lighting and Display Applications 9 10 Get White Blue + Phosphors Phosphor Reflector dish LED chip The phosphor converts some blue emission to yellow Blue and yellow light appears white Energy is lost in the process LED Supply Chain Changing Rapidly Materials Processes Devices Materials & Subsystems Materials & Subsystems Integration Full Systems Integration intensity Excitation from LED Emission from phosphor wavelength (nm) 11 Substrates/Epitaxy (L0) Sapphire, SiC Silicon GaN LED Device Designs (L1) Lateral Vertical Flipped (Lateral) Packaging (L2) Efficiency Thermals Cost Integration: Module (L3) Fixture (L4) System (L5) Design selections at any level impact down stream design options Rapid disruptive innovation across entire supply chain Packaging and Integration are now main cost barriers 12

4 Outline Introduction to Smart Lighting LED Packaging Challenges Anatomy of an LED Package Wire Bond Encapsulation Die Molding Compound Die Attach Leads Solder Pads Osram Golden Dragon Advances in LED Packaging Dielectric Heat Sink Solder Metal Board Summary Component Factors CTE matching Chemical compatibility Reflectivity Moisture absorption Thermal conductivity Photothermal stability Assembly Factors Cost of capital equipment Throughput (UPH) Cleaning Assembly Yield Testing Issues Metrics Lm/W & Lm/$$ Reliability Reflowable Pb free Size Packaging Many Challenges Lens/Window not shown Chip: Designs compatible with new die attach materials Efficient optical extraction designs for air cavity packages Efficient large chip with uniform current injection LED Lighting Fixtures Vertical LED chip Survive die attach CTE match of submount Die Attach Technology Compliance High Thermal Conductivity Electrically conductive Die Paddle High Thermal conductivity CTE Match Ideally, an insulator Package: Advanced die attach materials Methods for reducing thermal impedance at interfaces Die paddles with higher thermal conductivity than copper Ceiling with 16x8 array of LED Panels (128 panels): If constructed to the left, this single room would require 28,800 LEDs 15 16

5 Future Lighting Systems Requirements Light is not only for illumination, but also communication Adjustable color temperature: improved productivity and health Additional demands to color control may require even more dies per fixture: e.g. 3 individual LEDs instead of one LED + phosphor Outline Introduction to Smart Lighting LED Packaging Challenges Advances in LED Packaging Summary Surface Patterning of Non-Scattering Phosphor Improvements for LED Light-Extraction Efficiency High Refractive Index Nanoparticles (HRI NPs) into Silicone Based Encapsulants Neat silicone Light intensity excited by blue LED Incorporation of organic phosphor into NP systems (yellow emitting hybrid encapsulant) 300nm TiO2 pillars on YAG:Ce CPP etched by ICP-RIE A polymer-brush approach to compatibilize inorganic NPs (e.g. TiO 2, ZrO 2 ) with silicone Courtesy of Dr. An Mao and Prof. Robert F. Karlicek, Jr. 19 Courtesy of Ying Li, Prof. Linda Schadler 20

6 Lower Cost, High Speed Assembly Laser Based Die Printing Leverage progress in thin film package development? Transparent Substrate Moving receiver film Under development for thinned Si die (e.g. RFID) Capable of very high speeds Transfer only the die needed (LEDs, sensors, drivers ) Many details need to be worked out Nth Degree Screen Printed LED Lighting 21 Miller, R., V.R. Marinov, O. Swenson, Zh. Chen, M. Semler. "Noncontact Selective Laser Assisted Transfer of Thinned Semiconductor Tiles Using a Two Part Dynamic Releasing Layer." (to appear in IEEE Transactions on Components, Packaging and Manufacturing Technology, 2012) 22 Directed Self-Assembly Directed self-assembly media: air, liquid, air-liquid interface, interface between two liquids LED Assembly using Versuflex Nano-coating Tool S. B. Shetye, Dissertation, University of Florida W. Zheng, P. Buhlmann, H. O. Jacobs, University of Minnesota, PNAS, vol. 101 no , Aug Alien Technology Corp., White Paper, Oct

7 Directed Self-Assembly with Magnetic Force Make dies buoyant by providing them with a thick lightweight layer Functional Integration and assemble them on a flexible substrate in a roll-to-roll process using magnetic force 25 From Aaron Merrill, Bridgelux, Strategies in Light, Monolithic Optoelectronic Integration World s First Integrated GaN LED/HEMT Successfully demonstrated GaN LED driven by monolithically integrated GaN MOS-channel HEMT higher than 200 C Issues with Discrete Devices Slow Unreliable Inefficient Bulky Expensive Impact of Monolithic Integration Fewer parasitics Higher efficiency Smaller package Lower cost 27 *Z Li, et al., Appl. Phys. Lett. 102, (2013) 28

8 Integration for Cost Savings? Direct View LED Pixel Displays? 55 Display contains about 6M LEDs Addressable RGB LEDs create video image Artificial skylights and windows??? X. Fan, th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems, EuroSimE Illumination Video Fusion? Ultra-efficient Illumination & Video Capabilities Light based sensing Summary Solid State Lighting will join Internet of Things Apps will customize illumination and lighting systems sense and learn best lighting practices autonomously Smart Lighting Packaging technology is now in the critical path of solid state lighting development Some of the same drivers for the silicon packaging industry could be applied to future lighting systems Grid and Building Systems Integration Lighting based wireless data services (LiFi) From The Sky Factory High-speed assembly of tiny LEDs on large substrates is critical for cost reduction of smart lighting systems Fundamentally simple concepts are available, extreme high-yield assembly is required

9 Smart Lighting with LEDs The Right Light Where and When You Need It Lighting systems that think Acknowledgements Funding from the NSF & NYSTAR Colleagues at Rensselaer (lead) Boston University University of New Mexico The Smart Lighting ERC Industrial Members (24 Companies across the world supporting the Smart Lighting Vision) 33 34