NAND Flash Memory as Driver of Ubiquitous Portable Storage and Innovations

Transcription

1 NAND Flash Memory as Driver of Ubiquitous Portable Storage and Innovations aka: how we changed the world and the next chapter July 7, 2 Jian Chen Technical Executive, NAND System Engineering

2 Memory, Oh Memory You never know when you are making a memory 2

3 Outline History and Current Market Trend Low Cost NAND Flash Enables Multi Mega Markets NAND and MLC(Multi_Level_Cell) NAND Basics NAND Structure and Operations Technology Roadmap Challenges and Opportunities of Scaling NAND Flash as Technology Driver What It Takes to Success in This Business Conclusions 3

4 World s Early Solid State Non-Volatile Memories When there is civilization, there is need for non-volatile memory. Safest Job. Positives: Store Both Text and Images Great Data Retention Solid state, no moving parts Tools Simple and Low Cost Simple Process CMP & Dry Etch 荷 馬 史 詩 Homer's Iliad, Late 5th-early 6th B.C Negatives: High Cost, Not Portable Small Density and No Mass Market Slow Write Speed, Labor Intensive One Time Programmable No scaling for thousands of years 4

5 About SanDisk A Silicon Valley success story founded in 988, went public in 995 We only do Flash! We do Flash right. Vertically integrated: develop from bit cell to final systems to retail Famous for driving MLC, First MLC patent, first NAND MLC product Invented Compact Flash & co-developed SD/uSD etc industry standards Co-own two 3mm Mega Fabs with Toshiba, Announced Fab5 this week $3.6 Billion in revenue in 29 with over 3, employees worldwide Major portion of business is OEM: SanDisk inside SanDisk SSD in 8 of the top netbooks makers In some of the major SmartPhones 5

6 Then the Last 9 Years inch 2MB 35KB/sec $5/MB e.g. Space Shuttles Boeing 777 Black Box 25X! 2 x5xmm 32GB 2MB/sec ~$2/GB In Billions of People s Pockets 8Mbit.8um(~99) 6Mbit.5um 64Mbit/MLC.5um(995) 256Mbit/MLC.28 um (998) G/MLC.6um(2) 2G/MLC.3um(22) 4G/MLC 9nm(24) 8G/MLC 7nm(25) 6G/MLC 56nm(26) 32G/MLC 43nm(28) 64G/MLC 32nm(29) 64G/MLC 2xnm(2) 6

7 Revenue (Billions of Dollars) NAND Flash Market Forecast: 28 Collapse, 2+ Recovery CAGR 8-3 Petabytes ,992 4,53 6,336,27 22,565 42,73 76, % Bit Growth 258% 3 27% 77% 27% 4% 78% 98% 9% 8% % NAND Revenue 2.5% Pricing Could be More Conservative! 4.8% -4.8% 2.8% 2.9% 25.8% 2.4%.2% CAGR 8-3 ASP GB eqv % ASP Change -52.3% -63.3% -58.5% -62.4% -9.7% -3.5% -37.2% -4.6% -43.3% Source: Preliminary Gartner, November 29 Semiconductor Forecast Worldwide--Forecast Database [SEQS-WW-DB-DATA] 7

8 NAND Flash Demand Drivers: Mobile and SSD are Vital Thousands of PB Data Imaging Audio Video & Computing Lifestyle Storage, Digital Camera 8, 6, 4, Media Player USB Drive Camcorder Mobile Phone Gaming Computing 76,253 PB Driver Criteria - Units (M) - Capacity (GB) - Portable 2, Automotive Other - Durable - Power 9.9 PB - Performance Note: NAND flash consumption includes both in-system and removable storage such as flash cards. Source: Gartner November, 29 Semiconductor Forecast Worldwide--Forecast Database [SEQS-WW-DB-DATA] 8

9 The Most Exciting Time iphone/smartphones/droids/tablet = New PC Thin Is In, No HD 9

10 Flash Is Everywhere Already In the next decade, it will be BIGGER than you think!

11 Fab5 Huge Investment and Commitment: Not for the Faint of the Heart Fab Fab2 Fab3 Fab4

12 Outline History and Current Market Trend Low Cost NAND Flash Enables Multi Mega Markets NAND and MLC(Multi_Level_Cell) NAND Basics NAND Structure and Operations Technology Roadmap Challenges and Opportunities of Scaling NAND Flash as Technology Driver What It Takes to Success in This Business Conclusions 2

13 Fundamental NAND Flash Cell Operation Write and Erase by Fowler-Nordheim tunneling High write (program) and erase voltage needed, >2V 3

14 Block n NAND Read Operation BL BL BL2 BL3 WL3 SGD SGD WL3 WL3 WL29 Floating V Vread (5V) Vread Vread Vread 8KByte bit-lines are read at a time. Block n is the selected block. WL is the selected wordline. Vread turns on all the un-selected cells, regardless of its data. Read current flows through erased (or data ) cell. WL2 WL WL SGS CSL Vread Vcgrx (V for Bin) Vread Vread V 4

15 Block n NAND Program Operation Vdd V Vdd BL BL BL2 BL3 WL5 SGD SGD WL3 WL3 WL29 WL2 Floating V Vdd Vpass (9V) Vpass Vpass Vpass 8KByte bit-lines are pgm at a time. Block n is the selected block. WL is the selected wordline. BL 2 is the program bitline BL and 3 are program inhibited Example here is SB (Self-Boosting) Vpgm step up, so does Vpass Data= cells in WL is program disturbed Data= cells on BL 2 is programmed disturbed All other cells are Vpass disturbed WL WL SGS CSL Vpgm (~2V) Vpass V Vdd 5

16 6 x4 6 levels SLC 2 levels MLC 4 levels What Is MLC (Multi_Level_Cell) NAND 3 bits/cell 8 levels Cost Goes Down System Expertise Increasingly Important

17 Key Attributes of NAND Flash Memory Making it the Driver of Ubiquitous Portable Storage Mega Markets Lowest Cost Simplest cell structure Smallest cell with SA-STI (4F 2 ), close to litho defined minimum 2F 2 with 2bits MLC, 8 generations of volume production 3bits with even most cost down, 3 generations of product shipped Best Suitable for Portable Storage Media No moving part Low power and high speed programming/erasing Single bit program slow (2us), but can program 32KB at same time High Reliability Best media to be managed by flexible system The above attributes has enabled several growing Mega Markets DSC, USB drives, MP3, Gaming, Digital Video, Hand Sets and Mobile Phone, SmartPhone, Tablet yet unknown applications. 7

18 Outline History and Current Market Trend Low Cost NAND Flash Enables Multi Mega Markets NAND and MLC(Multi_Level_Cell) NAND Basics NAND Structure and Operations Technology Roadmap Challenges and Opportunities of Scaling NAND Flash as Technology Driver What It Takes to Success in This Business Conclusions 8

19 It s Getting Harder: Heaven for Fun Loving Engineers Getting Harder and Harder: Lagging lithography technology Coupling ratio and high program voltage Floating to Floating gate coupling with scaling Less and less e- in sub-3nm memories Vth fluctuation due to random telegraph signal with scaling Gate delays, new materials STI Fillings Contact: high AR ratio for etch, clean and fill IPD, tunnel oxide scaling Equipment variations $$$ equipments Test cost Random perf. requirements Sys. design for perf. and reliability Innovations! 9

20 Flash Management Know-How Required Manufacturing/Accumulated Bad Blocks Bad-Block Management Write/Erase Cycles Limitation Static Wear-Leveling Bit Flips Error Detection/ Error Correction Likelihood of Flash Wear Depends on Use Dynamic Wear-Leveling Limited Data Retention Active Data Refresh Self Monitoring & reporting S.M.A.R.T Challenge increases as process shrinks 2

21 Advantage of Vertical Integration The building blocks make the difference! 2

22 Conclusions Amazing Journey the Last 2 years For NVM and esp. NAND Flash Low Cost MLC NAND Enabled Multi Mega Markets Crude Oil of the Mobile Information Age Yet Growing Challenges for NAND Scaling, for System/Process/Device/Design/Test Engineers Vertical Integration Is the Best Approach NAND Is Everywhere Will BIGGER Than We Think 22

23 Thank You! NAND Everywhere Core Digital Imaging Personal Data Storage Digital Audio Mobile Phones Gaming Best Better SanDisk Extreme Family Cruzer Titanium II Sansa TM e2 Memory Stick PRO Duo Memory Stick PRO Duo SanDisk Ultra Family Cruzer Micro II Sansa TM c minisd MMCmobile SD Good Blue Family Cruzer Micro Skins Sansa TM m2 microsd inand Cruzer Crossfire Shoot & Store Family Cruzer Mini Sansa e 23