Thermal challenges in IC s: Hot spots passive cooling and beyond Devesh Mathur, Ph.D. Andy Delano, Ph.D. Honeywell Electronic Materials Spokane, WA, USA February 15, 2007
Overview Motivation Where are the thermally challenged IC s? Cooling IC s today Cooling IC s in the future How do we get there? Conclusions 2 Devesh Mathur & Andy Delano HONEYWELL CONFIDENTIAL 2/15/2007 MEPTEC
Microprocessor Applications IC s are pervasive in various applications 3 Devesh Mathur & Andy Delano HONEYWELL CONFIDENTIAL 2/15/2007 MEPTEC
All Rely on Chips 10 billion square inches of silicon forecast for 2009 4 Devesh Mathur & Andy Delano HONEYWELL CONFIDENTIAL 2/15/2007 MEPTEC
Putting the Heat Flux Challenge into Perspective 10000 Heat Flux (W/cm 2 ) 1000 100 10 1 0.1 Sunlight on a Tropical Beach 0.01 0 500 1000 1500 2000 2500 3000 Temperature ( o C) 5 Devesh Mathur & Andy Delano HONEYWELL CONFIDENTIAL 2/15/2007 MEPTEC
Putting the Heat Flux Challenge into Perspective 10000 Shuttle Re-entry Heat Flux (W/cm 2 ) 1000 100 10 1 0.1 Sunlight on a Tropical Beach 0.01 0 500 1000 1500 2000 2500 3000 Temperature ( o C) 1 Megaton at 1 mile 6 Devesh Mathur & Andy Delano HONEYWELL CONFIDENTIAL 2/15/2007 MEPTEC
Putting the Heat Flux Challenge into Perspective 10000 Shuttle Re-entry Heat Flux (W/cm 2 ) 1000 100 10 1 0.1 Rocket Nozzle Throat Sunlight on a Tropical Beach 0.01 0 500 1000 1500 2000 2500 3000 Temperature ( o C) 1 Megaton at 1 mile 7 Devesh Mathur & Andy Delano HONEYWELL CONFIDENTIAL 2/15/2007 MEPTEC
Putting the Heat Flux Challenge into Perspective Tomorrow s Microprocessors 10000 Shuttle Re-entry Heat Flux (W/cm 2 ) 1000 100 10 1 0.1 Rocket Nozzle Throat Sunlight on a Tropical Beach 0.01 0 500 1000 1500 2000 2500 3000 Temperature ( o C) The thermal challenge in an IC is a truly daunting problem 1 Megaton at 1 mile 8 Devesh Mathur & Andy Delano HONEYWELL CONFIDENTIAL 2/15/2007 MEPTEC
Motivation: CPU Heat Flux is High IR image of an actual processor Most heat leaves through center 15% of the spreader s surface area 9 Devesh Mathur & Andy Delano HONEYWELL CONFIDENTIAL 2/15/2007 MEPTEC
Motivation: CPU Power is Steadily Increasing ITRS Power Predictions 3000 130 nm 90 nm 65 nm 45 nm 32 nm 2500 W or W/cm 2 2000 1500 1000 500 0 2002 2004 2006 2008 2010 2012 2014 2016 2018 Year Total Power (W) Heat Flux (W/cm^2) Flux at the core continues to rise despite design innovation 10 Devesh Mathur & Andy Delano HONEYWELL CONFIDENTIAL 2/15/2007 MEPTEC
Where are the thermally challenged IC s? Picture of a Workstation Chipset Graphics Processor Unit (GPU) Central Processor Unit(s) AMB Memory Thermal solutions are required for the CPU and ASIC s 11 Devesh Mathur & Andy Delano HONEYWELL CONFIDENTIAL 2/15/2007 MEPTEC
Memory: AMB IC AMB IC is HOT IC: Bare die Power: 4-8 Watts Airflow: System dependent, usually compromised - Sometimes cards are perpendicular to flow - In servers and workstations, many cards are packed densely together Thermal Solution: TIM and a heat spreader Up to 16 Memory Cards Memory cards require thermal solutions and system level attention 12 Devesh Mathur & Andy Delano HONEYWELL CONFIDENTIAL 2/15/2007 MEPTEC
The Most Critical Heat Pathways Typical Thermal Budget 0.60 0.50 Pre Heat, 0.100 Thermal Interface Material 0.40 Heat Spreader θ ( C/W) 0.30 Heat Sink Fins, 0.100 Heat Sink Base, 0.100 Thermal Interface Material 0.20 0.10 { TIM2, 0.050 Heat Spreader, 0.100 0.00 TIM 1, 0.050 The highest heat fluxes travel through 0.20 C/W of the total budget 13 Devesh Mathur & Andy Delano HONEYWELL CONFIDENTIAL 2/15/2007 MEPTEC
Classical Packaging Limits Classical Package consists of: - TIM1 - Heat Spreader - TIM2 Typical limitations - TIM1 Heat Spreader Flatness Heat Spreader Surface - Heat Spreader Spreading Resistance CTE mismatch - TIM2 Heat Spreader Flatness Heat Spreader Surface C/W 0.25 0.2 0.15 0.1 0.05 θ junction to heat sink where we are vs. best in class 0.20 0.06 0 Typical Modeled Best in Class Room to improve classical package with improved technology 14 Devesh Mathur & Andy Delano HONEYWELL CONFIDENTIAL 2/15/2007 MEPTEC
Materials Roadmap for Critical Heat Pathways -2004------------------------ 2006---------------------------2008+ Thermal Interface Material Heat Spreader Thermal Interface Material HEM produces and develops products for critical heat pathways The products control at least 0.20 C/W of the total budget 15 Devesh Mathur & Andy Delano HONEYWELL CONFIDENTIAL 2/15/2007 MEPTEC
Memory Module Heat Sink: Thermal Modeling Actual Memory Heat Sink Is TIM1 important to the AMB? 3D CAD Model for Mechanical FEA Analysis 16 Devesh Mathur & Andy Delano HONEYWELL CONFIDENTIAL 2/15/2007 MEPTEC
TIM 1 Performance: Memory Module Honeywell PCM45 Competitor s Material FEA results predict >10 C reduction on AMB chip, allowing superior performance 17 Devesh Mathur & Andy Delano HONEYWELL CONFIDENTIAL 2/15/2007 MEPTEC
Honeywell s TIM s* Thermal Impedence (C-cm2/W) 0.50 0.45 0.40 0.35 0.30 0.25 0.20 0.15 0.10 0.05 0.00 PCM45F- Pad PCM45F-SP (Polymer Filled) APS (Advanced Polymer Solder) PCM- Next Generation (Polymer Filled) 0 1 2 3 4 5 6 7 8 9 10 Bondline Thickness (BLT), mil Indium- Combo (Pb Free- Metallic) *Actual Data may vary in application. ASTM D-5470 HEM representative products cover a wide performance range to help address thermal challenges 18 Devesh Mathur & Andy Delano HONEYWELL CONFIDENTIAL 2/15/2007 MEPTEC
Collaboration is key to Innovation People External Forces Competition Academia Industry Rapid and fundamental innovation requires increased collaboration 19 Devesh Mathur & Andy Delano HONEYWELL CONFIDENTIAL 2/15/2007 MEPTEC
Collaboration: example CTRC Purpose: Long term research and development in the area of high-performance heat removal from compact spaces - NSF Industry/ University cooperative research center at Purdue University Path - Attend bi-annual CTRC meetings to review work - Determine and support relevant technologies - Productize Products - Optimized particle TIMS - CNT TIMS - Advanced Heat Spreaders Progress - Member since 2002 - Hired CTRC graduate Boiling Research Particulate TIM Models Source: CTRC, Purdue. Used with permission. Industry issues worked on fundamentally to address challenges 20 Devesh Mathur & Andy Delano HONEYWELL CONFIDENTIAL 2/15/2007 MEPTEC
Thermoelectrics: example Nextreme Active Cooling Thin film thermoelectric device operates between the heat spreader and IC Hot spots are addressed with refrigeration - Heat flux into heat spreader increases, however, hot spot temperature is reduced - Some additional power is required Challenges - Improving TE materials - Understanding Reliability Source: Nextreme, used with permission. Nextreme s etec for Hotspot Cooling With improved materials and reliability, thermoelectric devices could revolutionize hot spot cooling 21 Devesh Mathur & Andy Delano HONEYWELL CONFIDENTIAL 2/15/2007 MEPTEC
New: Honeywell s Active Heat Spreader Improving the Heat Spreader Improves the performance of everything downstream Standard Heat Spreader T max = 81.2 C Enhanced Heat Spreader T max = 63.4 C Significant (17.8 C) reduction over current technology 22 Devesh Mathur & Andy Delano HONEYWELL CONFIDENTIAL 2/15/2007 MEPTEC
Other Innovations Power limitations for chip architects Software and threading innovation Data center power balancing Discrete device computing Multi die and multi core Feedback loops, throttling, and thermal shutdown Smart chip & system design can also address thermal challenges 23 Devesh Mathur & Andy Delano HONEYWELL CONFIDENTIAL 2/15/2007 MEPTEC
Thermal Management at the IC Level This technique is currently used in: - mobile computers - CPU s - AMB s (DIMMs) Shutdown Permanent thermal damage Power rationing Fan speed control IC Temperature!!Computing errors!! Reduced performance and reliability In-spec performance and reliability Low db acoustics Power management can improve thermals, but will reduce performance 24 Devesh Mathur & Andy Delano HONEYWELL CONFIDENTIAL 2/15/2007 MEPTEC
Summary Thermally Challenged IC s found throughout modern computers - CPU - ASIC s GPU Memory Chipsets Overall Heat Flux and Hot Spots are pushing the limits of today s products Some of today s cutting-edge products address the thermal challenge today Next generation products offer hope. Collaboration is key. Innovation in thermal management will enable better performance 25 Devesh Mathur & Andy Delano HONEYWELL CONFIDENTIAL 2/15/2007 MEPTEC
Summary Thermally Challenged IC s found throughout modern computers - CPU - ASIC s GPU Memory Chipsets Overall Heat Flux and Hot Spots are pushing the limits of today s products Some of today s cutting-edge products address the thermal challenge today Next generation products offer hope. Collaboration is key. Innovation in thermal management will enable better performance 26 Devesh Mathur & Andy Delano HONEYWELL CONFIDENTIAL 2/15/2007 MEPTEC