Mems mass storage syatem


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  • CMU solution is most complex of three-must control individual heights of 6,400 probe tips,required by recording technology
  • Mems mass storage syatem

    1. 1. MEMS BASED INTEGRATED CIRCUITMASS STORAGE SYSTEMS Presented by prashant singh (imi2011003)
    2. 2. HighlightsNew secondary storage technology that could revolutionize computer architecture. -Faster than hard drives -Lower entry cost -Lower weight and volume -Lower power consumptionDiscuss physical description of device.
    3. 3. Disk Drive limitationsDisk-drive capacities double every 18 months -better 60% per year growth rate of semiconductor memoriesTwo major limitations of disk drives are….. -Access times decreases have been minimal -Minimum entry cost remains too high for many applications
    4. 4. Problem SpecificationRequirement of mass storage system that can break both barrier -Access times -Minimum entry costNew mass storage should also be significantly cheaper than non-volatile RAM -$100 now buys 1 GB of flash memory
    5. 5. MEMSMEMS use -Same parallel wafer-fabrication process as semiconductor memories -Keeps the prices low -Same mechanical positioning of R/W heads as disk drives -Data can be stored using higher density thin film technology
    6. 6. Main Advantages Of MEMS Potential for dramatic decrease in -Entry cost(10x cheaper than RAM) -Access time -Volume -Mass -Power dissipation -Failure rate -Shock sensitivity Integrate storage with computation -Complete system-on-chip integration -Processing unit -RAM -Non-volatile storage
    7. 7. MEMS storage prototypeLike a disk drive, it has -recording heads -a moving magnetic recording mediumMajor departures from disk drive architecture are -MEMS recording heads-probe tips-are fabricated in a parallel wafer level manufacturing process -Media surface does not rotate(Data latency decreases)
    8. 8. Data Organization disk MEMS
    9. 9. Media Surface MovementMedia surface that rotate requires ball bearingsVery small ball bearing may have “striction” problem that prevent accurate positioning -Element would move by sticking and slippingBest solution is to have media sled moving in X-Y directions -Sled moves in Y-direction for data access -Sled is suspended by spring
    10. 10. Conceptual View of “Moving Media”(CMU prototype) Read/Write Read/writeActuators tips tips Springs Magnetic Media Bits stored Media underneath side view each tip
    11. 11. Operation (A) (B) (C) (D) (E) (F)
    12. 12. The Media SledActuator pull sled in both dimensionsSize 8mm X 8mm X 500µmHeld over the probe tip array by a network of springsMotion applied through electrostatic actuators -Motion limited to 10% or less of suspension/actuator length -Each probe tip can sweep 1% of the media sledInclude large number of probe tips for -Improving data throughput -Increasing system reliability Read write operation
    13. 13. Probe Tip Positioning Most MEMS include some form of tip height control because -Media surface is not perfectly flat -Probe tip height may varyCMU(Carnegie Mellon University,Pennsylvania,US) prototype places each probe tip on a separate cantilever -Cantilever is electrostatically actuated to a fixed distance from the media surfaceIBM Millipede -Uses 32 x 32 array of probe tips -Each tip is placed at the end of a flexible cantilever -Cantilever bends when tip touches surfaceHP design places media surface and probe tips sufficiently apart IBM Millipede -No need to control probe tips height
    14. 14. Probe Tip FabricationMajor challenge is fabricating read/write probe tips in a way that is compatible with the underlying CMOS circuitryThis includes -thermal compatibility -geometrical compatibility -chemical compatibility……..
    15. 15. Failure ManagementMEMS devices will have internal failures -Tips will break during fabrication/assembly, use -Media can wear(erosion/sideways displacement)
    16. 16. Storing, Reading and Writing BitsCMU prototype uses same magnetic recording technology as current disk drives -Minimum mark size around 80µm x 80µmOther solutions include -Melting pits in a polymer (IBM Millipede) -Raises tip wear issues
    17. 17. Potential ApplicationLighter and less shock sensitive than disk drives -Great for notebook PC’s,PDA’s and video camcordersLower cost than disk drives in 1 to 10 GB range -Will open many new applicationsHigh areal densities -Great for storing huge amounts of dataCan combine computing and storage on a single chip E.g. Average service time around 0.52 ms -Disk drive service time is 10.1 ms -Key factor for service time is X-seek time
    18. 18. Thank You