Thermal Considerations in Package Stacking and Advanced Module Technology Ulrich Hansen, Director of Marketing, Staktek February 16, 2006
Continued drive to increase sub-system density, functionality and performance Desire to differentiate systems and derive time-to-market advantages System-level power consumption increases Cooling challenges Dedicated low-power devices emerging Mobile systems volumes increasing Form factor constraints increase the need for utilizing 3 rd dimension Supply Chain complexities Trends in Electronics Sub-Systems Thermal concerns are usually on top of the list when designing high-density sub-systems New supplier entrants, capacity planning challenges, forecasting accuracy limitations 2
Today s Example: High-Density DIMM The DRAM market continues to go through rapid technology change increasing the thermal and signal integrity complexities with each transition Continued drive to increase sub-system functionality and performance System-level power consumption increases Mobile systems increasing Supply Chain complexities DRAM speeds to DDR2-667 in mid-2006, followed by DDR2-800 and DDR3 Module capacity moving to 2GB and 4GB Transition to Fully-Buffered DIMMs in 2006 FB-DIMM adds ~6W AMB device to each DIMM and adds thickness / reduces airflow Max AMB case temperature of 110C Max DRAM case temperature of 85C DRAM speed and module capacity increases drive module power consumption Increasing airflow drives acoustics challenge (e.g. workstations) High-density SO-DIMM, Mini SO-DIMM for mobile applications are emerging DRAM prices continue to fluctuate as fab capacity and demand change Timing of market introductions uncertain as often coupled to chipset launches 3
Staktek s Core Technology: Device Stacking Today, Staktek s Stakpak is a market leading high-density DRAM technology Solves problem of high-device density in fixed DIMM form factor Great supply chain flexibility Same, standard device used in both highdensity and standard DIMMs Mature and cost effective Uses mature DRAM devices High-volume manufacturing (>175M Staktek stacks shipped) FBGA Stacking TSOP Stacking Well suited for current and future high-density DIMMs, but is there a better solution for thermally challenged systems? 4
High-Density Technology Options Advanced packaging by itself does not address the thermal challenges and introduces additional technical and economical challenges Remaining Questions Device Stacking PoP Package Dual-Die Package Thermal Performance? Thermal Performance? Thermal Performance Thickness? High-Speed Signal Integrity? Thickness? Direct Cost (e.g. non-standard manufacturing processes, single source) Direct Cost (e.g. single source) Supply Chain Cost (e.g. obsolescence, opportunity cost) Technology Maturity DIMM Sub- System Design Optimization Needed Supply Chain Cost (e.g. obsolescence, opportunity cost) Time-to-Market? Time-to-Market 5
Module Technology The DIMM is a module technology that utilizes a double-sided, flexible circuit with an integrated edge connector folded around a rigid thermal core 6
The modules deliver a number of significant, system-level benefits Double Surface Area α High-Density Benefits Thinner Profile α Less motherboard space while meeting thermal requirements Thermally Enhanced α Less Cooling (less Costly, Quieter) Improved Electrical α Better High-Speed Margins Highly Durable α Improved Reliability and Handling Yield JEDEC / RoHS Compliant α Standards Compliant, Sourcing Flexibility Next-Gen Module Technology α Future Proof 7
Thinness s thinness contributes to better thermal performance for the same DIMM socket pitch JEDEC MAX Conventional FBDIMMs 2-Rank Stack 1 Rank FBDIMM 2-Rank Planar 2-Rank 2-Rank 2-Rank Planar 2 -Rank Planar Thermally Enhanced 8.8 mm. 8.2 mm. 7.65 mm. 6.2 mm. 6.2 mm. 4.5 mm. 4.5 mm. 10.16 mm. FBDIMMs are thinner than conventional FBDIMMs enables narrower DIMM connector pitch while maintaining airflow FBDIMM up to 48% thinner RDIMM up to 20% thinner 8
Thermal Results RDIMM s provide improved thermal mass, radiating area and thermal coupling Thermal core pulls heat back along the DIMM Less temperature spread between DRAMs: Coolest not as cool, hottest not as hot FR4 DIMM w/ Package Stacking 9
FBDIMMs can be cooled with with lower Airflow Thermal Results vs. Conventional FBDIMM (JEDEC R/C E) 140 Max DRAM Temp * 140 AMB 135 130 135 130 Dual Die w/ AMB HS Case Temperature 125 120 115 110 105 100 95 90 Planar w/ AMB HS Dual Die w/ AMB HS Case Temperature 125 120 115 110 105 100 95 90 38mm Planar w/ AMB HS 85 80 75 38mm 85 80 75 70 65 1 m/s 2 m/s 3 m/s 4 m/s 5 m/s 6 m/s Note: * Full-Module Heat Spreaders can be applied to further lower the DRAM temperature 70 65 Conditions : Inlet Air 50C Power 16.8W 1 m/s 2 m/s 3 m/s 4 m/s 5 m/s 6 AMB m/s 6W DRAMs 36 @ 300mW Pitch 10.16 mm 10
Electrical Results s electrical properties are exceptional compared to conventional printed circuit boards. The interconnect environment of the flexible circuit, with its tight spacing and effective dielectrics, is tailored for high-speed signal propagation at ultra-low crosstalk levels. Conventional Conditions: Post Register Address on JEDEC Raw Card-J RDIMM @ DDR2-533 11
Advanced Module Technology Additional Applications Most mobile devices represent form factor challenges as more and more features move into the products Sample Sub-Systems Applications Processor (Micro, DSP) + DRAM Processor + DRAM + FLASH Processor + ASIC ASIC + DRAM + FLASH ASIC + Imager + DRAM MP3 + FLASH MP3 + GPS + FLASH MP3 + Radio (Bluetooth, WiFi, Cellular) Computing Medical Telecommunication Defense Consumer Electronics: MP3 Player Cell Phone GPS Digital Camera Digital Video 12
Example: Processor + DRAM We apply our experience of >175M device stacks to develop and implement highly standardized manufacturing processes Standard SMT processes to assemble & test flat DRAM 2 Processor Illustrative DRAM 1 Simple fold step with adhesive utilizing a auto / semi-auto precision fold tool Fold step with thermal core inserted Thermal Core 13
Advanced Packaging Advanced module technology provides time-to-market advantages for nextgeneration feature integration often in conjunction with advanced packaging 3-Device System Stakpak Thinner, 2-Device System Stakpak Planar Feature A (e.g. MP3) Feature B (e.g. GPS) Feature C Features A + B + (e.g. Flash) + 3D Packaging or Chip-Integration (Single Die) Feature C Features A + B + C 3D Packaging or Chip-Integration (Single Die) Next-Generation Product 3-Device System Stakpak Thinner, 2-Device System Stakpak Add Feature D Features A + B Package 1 + Feature C Package 2 Feature D Features A + B + C Package 1 + Feature D Package 2 Package 3 14
Staktek is a technology IP company providing solutions for sub-system form factor optimization, including thermal optimization DIMMs have superior thermal performance and provide headroom to scale into next-generation DRAM speeds DIMMs are a great example of Staktek s sub-system optimization in a given, fixed form factor Sub-system optimization has many applications, e.g. in form-factor constraint mobile devices Summary Staktek s System Stakpak is a flexible architecture to deliver subsystem optimization, including thermal solutions with integrated cores Meets form factor requirements Low risk, low investment standard manufacturing processes Time-to-market advantage prior to package-level optimization Accommodates regular or advanced packages 15