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ITRS-2001 Design ITWG July 18, 2001 Europe: W. Weber Japan: Y. Furui, T. Kadowaki, H. Taguchi, K. Uchiyama USA: A. Kahng, K. Kolwicz. System Drivers Chapter. Define IC products that drive mfg, design technologies Replace the 1999 SOC Chapter
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ITRS-2001 Design ITWGJuly 18, 2001Europe: W. WeberJapan: Y. Furui, T. Kadowaki, H. Taguchi, K. UchiyamaUSA: A. Kahng, K. Kolwicz
System Drivers Chapter • Define IC products that drive mfg, design technologies • Replace the 1999 SOC Chapter • ORTCs + SDs = “consistent framework for tech requirements” • Four system drivers • (HVC) MPU – traditional processor core • SOC (focus on “ASIC-LP”, + high-pins, high-signaling network driver) • AM/S – four basic circuits and FOMs • (HVC) DRAM • Each driver section • Nature, evolution, formal definition of this driver • What market forces apply to this driver ? • What technology elements (process, device, design) does this drive? • Key figures of merit, and roadmap • Working text material (handout): (MPU) , (SOC) , AMS • Inputs from Test, A&P, Litho/PIDS/FEP, Interconnect
MPU Driver • Old MPU model – 3 flavors • New MPU model - 2 flavors • Cost-performance at production (CP) • 140 mm2 die, “desktop” • High-performance at production (HP) • 310 mm2 die, “server” • Both have multiple cores (“helper engines”), on-board L3 cache, … • Multi-cores == more dedicated, less general-purpose logic; driven by power and reuse considerations; reflect convergence of MPU and SOC • Doubling of transistor counts is each per each node, NOT per each 18 months • Clock frequencies stop doubling with each node
Example Supporting Analyses (MPU) • Diminishing returns • Pollack’s Rule: In a given process technology, new microarchitecture takes 2-3x area of previous generation one, and provides only 50% more performance • Corroboration: SPECint/MHz, SPECfp/MHz, SPECint/Watt all decreasing • Power knob running out • Speed == Power • Large switching currents, large power surges on wakeup, IR drop control issues all limited by A&P roadmap (e.g., improvement in bump pitch, package power) • Power management: 2500% improvement needed by 2016 • Speed knob running out (new clock frequency model) • Historically, 2x clock frequency every node • 1.4x/node from device scaling but running into tox, other limits (PIDS) • 1.4x/node from fewer logic stages (from 40-100 down to around 14 FO4 INV delays) • Clocks cannot be generated with period < 6-8 FO4 INV delays • Pipelining overhead (1-1.5 FO4 INV delay for pulse-mode latch, 2-3 for FF) • Around16 FO4 INV delays is limit for clock period in core (L1 $ access, 64b add) • Cannot continue 2x frequency per node trend in ITRS
Example Supporting Analyses (MPU) • Logic Density: Average size of 4t gate = 32MP2 = 320F2 • MP = lower-level contacted metal pitch • F = min feature size (technology node) • 32 = 8 tracks standard-cell height times 4 tracks width (average NAND2) • Additional whitespace factor = 2x (i.e., 100% overhead) • Custom layout density = 1.25x semi-custom layout density • SRAM Density:(used in MPU) • bitcell area (units of F^2) near flat: 223.19*F (um) + 97.748 • peripheral overhead = 60% • memory content is increasing (driver: power) and increasingly fragmented • will see paradigm shifts in architecture/stacking; eDRAM, 1-T SRAM, 3D integ… • Significant SRAM density increase, slight Logic density decrease, compared to 1999 ITRS • 130nm node: old ASIC logic density = 13M tx/cm2, new = 11.6M tx/cm2 • 130nm node: old SRAM density = 70M tx/cm2, new = 140M tx/cm2 • Chief impact: power densities, logic-memory balance on chip
SOC-LP Driver (STRJ) • Power gap • Must reduce dynamic and static power to avoid zero logic content limit • Hits low-power SOC before hits MPU • SOC degree of freedom: low-power (not high-perf) process • SOC-LP model drives ASIC-LP (PIDS) device model • Lgate lags high-performance devices by 2 years • Accompanying device parameter changes • Vth higher (up to .5 x Vdd limit) • Ig, Ioff starts at 100pA/um (L(Operating)P), 1pA/um (L(STandby)P) • Tox higher • Slower devices (higher CV/I) • Four LP device flavors: Design still faces 40-1000%/node static power management challenge, and must address multi (Vt,tox,Vdd) • SOC-LP driver: low-power PDA • Composition: CPU cores, embedded cores, SRAM/eDRAM • Roadmap for IO bandwidth, processing power, GOPS/mW efficiency • Die size grows at 20% per node
SOC-LP Driver Model • Required performance trend of SOC-LP PDA driver • Drives PIDS/FEP LP device roadmap, Design power management challenges
Mixed-Signal Driver(Europe) Ralf Brederlow°, Stephane Donnay+,Joseph Sauerer#, Maarten Vertregt*,Piet Wambacq+, and Werner Weber° °Infineon Technologies, +IMEC, #Fraunhofer-Instutitut for Integrated Circuits , *Philips Semiconductor
Overview • Today, the digital part of circuits is most critical for performance and is dominating chip area • But in many new IC-products the mixed-signal part becomes important for performance and cost • This shift in paradigms leads to the need for a definition of the analog boundary conditions in the design part of the ITRS roadmap • The goal is to define criteria for needs of future analog/RF circuit performance and compare it to device parameters: • choose critical and important analog/RF circuits • identify circuit performance needs • and related device parameter needs
Concept for the Mixed-Signal-Roadmap • Figures of merit for four important basic analog building blocks are defined and estimated for future circuit design • From these figures of merit related future device parameter needs are estimated (PIDS-table partially owned by design) … … Roadmap for basic analog / RF circuits Roadmap for device parameter (needs) … … A/D-Converter Lmin 2001 … 2015 Low-Noise Amplifier Voltage-Controlled Oscillator mixed-signal device parameter Power Amplifier
Figure of Merit for LNAs • LNA performance: • dynamic range • power consumption G gain NF noise figure IIP3 third order intercept point P dc supply power f frequency
Figure of Merit for VCOs • VCO performance: • timing jitter • power consumption f0 carrier frequency Df frequency offset from f0 L{Df } phase noise P supply power
Figure of Merit for PAs • PA performance: • output power • power consumption Pout output power G gain PAE power added efficiency IIP3 third order intercept point f frequency
13 10 12 10 FoM ADC [1/Joule] 11 10 10 10 1990 1995 2000 2005 2010 2015 year of publication Figure of Merit for ADCs • ADC performance: • dynamic range • bandwidth • power consumption ENOB0 effective number of bits fsample sampling frequency ERBW effective resolution bandwidth Psupply power
22 1 kW super audio 1mW 1 W 20 18 audio GSM Basestation 16 GSM 14 Resolution(bit) Cable DTV 12 1 mW UMTS 10 Storage telephony 8 Bluetooth Intercon-nectivity 6 video 4 1kHz 10kHz 100kHz 1MHz 10MHz 100MHz 1GHz Signal Bandwidth Mixed-Signal Market Drivers System drivers for mass markets can be identified from the FoM approach
Design Chapter Outline • Introduction • Scope of design technology • Complexities (silicon, system, design process) • How design technology is driven by System Drivers • Design Grand Challenges • Details of challenges/needs and potential solutions (metrics) • One section for each of: • Design Process (quality/cost model ) • Functional Verification (escapes, fault tolerance) • System-Level (embedded software productivity, reuse, quality) • Logical/Physical/Circuit (power management, AM/S circuit FOMs) • Test (%BIST, …) • In each section: • Overview of detailed issues and challenges • Near-term / long-term needs related to driver classes • Key quality metrics (tables or figures)
Design Grand Challenges > 65nm • Scaling of maximum-quality design implementation productivity • Overall design productivity of quality- (difficulty-) normalized functions on chip must scale at 2x / node • Reuse (including migration) of design, verification and test effort must scale at > 2x/node • Develop analog and mixed-signal synthesis, verification and test • Embedded software productivity • Power Management • Off-currents in low-power devices increase 10x/node; design technology must maintain constant static power • Power dissipation for HP MPU exceeds package limits by 25x in 15 years; design technology must achieve power limits • Power optimizations must simultaneously and fully exploit many degrees of freedom - multi-Vt, multi-Tox, multi-Vdd in core - while guiding architecture, OS and software • Deeper integration of Design technology with other ITRS technology areas • Example: Die-package co-optimization • Example: Design for Manufacturability (sharing variability burden with Litho/PIDS/FEP and Interconnect, reduction of system NRE cost) • Example: Design for Test
Design Grand Challenges < 65nm • (Three Grand Challenges from > 65nm, and) • Noise Management • Lower noise headroom especially in low-power devices; coupled interconnects; supply voltage IR drop and ground bounce; thermal impact on device off-currents and interconnect resistivities; mutual inductance; substrate coupling; single-event upset (alpha particle); increased use of dynamic logic families • Modeling, analysis and estimation at all levels of design • Error-Tolerant Design • Relaxing 100% correctness requirement may reduce manufacturing, verification, test costs • Both transient and permanent failures of signals, logic values, devices, interconnects • Novel techniques: adaptive and self-correcting / self-repairing circuits, use of on-chip reconfigurability
Design Cost Analysis • “Largest possible ASIC” design cost model (Dataquest) • engineer cost per year increases 5% per year ($181,568 in 1990) • EDA tool cost per year increases 3.9% per year ($99,301 in 1990) • #Gates in largest ASIC/SOC design (.25M in 1990, 250M in 2005) • %Logic Gates constant at 70% • #Engineers / Million Logic Gates decreasing from 250 in 1990 to 5 in 2005 • Productivity due to 8 major Design Technology innovations (3.5 of which are still unavailable) : RTL methodology; In-house P&R; Tall-thin engineer; Small-block reuse; Large-block reuse; IC implementation suite; Intelligent testbench; ES-level methodology • Small refinements: (1) memory content; (2) other design NRE (mask cost, etc.) • #Engineers per ASIC design still rising 20x in 15 years despite assumed 50x improvement in designer productivity
Design Cost and Quality Requirement • Design cost of “largest ASIC” rises despite major DT innovations • Other Dataquest #’s confirm slight increase in memory content • Must complement with requirements for design quality
Design Quality Model • “Normalized transistor” quality model normalizes: • speed, power, density in a given technology • analog vs. digital • custom vs. semi-custom vs. generated • first-silicon success • other: simple / complex clocking, verification/test effort and coverage, manufacturing cost, … • Design process quality model: in development • Many private commercial and/or in-house analogues • Survey methodology being used (US, MARCO GSRC)