NAND Flash Memory as Driver of Ubiquitous Portable...

July 17, 2010

NAND Flash Memory as Driver of

Ubiquitous Portable Storage and

Innovations

Jian ChenTechnical Executive, NAND System Engineering

aka: how we changed the world and the next chapter

2

Memory, Oh Memory

You never know when you are

making a memory

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

4

World’s Early Solid State Non-Volatile Memories

荷馬史詩Homer's Iliad, Late 5th-early 6th B.C

Positives:

• Store Both Text and Images

• Great Data Retention

• Solid state, no moving parts

• Tools Simple and Low Cost

• Simple Process– CMP & “Dry Etch”

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

When there is civilization, there is need for non-volatile memory. Safest Job.

5

About SanDisk

▶ A Silicon Valley success story – founded in 1988, went public in 1995

▶ 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 300mm Mega Fabs with Toshiba, Announced Fab5 this week

▶ $3.6 Billion in revenue in 2009 with over 3,000 employees worldwide

▶ Major portion of business is OEM: SanDisk inside

▶ SanDisk SSD in 8 of the 10 top netbooks makers

▶ In some of the major SmartPhones

6

Then the Last 19 Years…

19912.5 inch20MB

35KB/sec$50/MB

201011x15x1mm

32GB20MB/sec~$2/GB

e.g. Space ShuttlesBoeing 777 Black Box

In Billions of People’s Pockets

25000X!

8Mbit

0.8um(~1991)16Mbit

0.5um

64Mbit/MLC0.5um(1995)

256Mbit/MLC0.28 um (1998)

8G/MLC70nm(2005)1G/MLC

0.16um(2001)2G/MLC

0.13um(2002)4G/MLC

90nm(2004)

16G/MLC56nm(2006)

32G/MLC43nm(2008)

64G/MLC32nm(2009)

64G/MLC2xnm(2010)

7

NAND Flash Market Forecast:

2008 Collapse, 2010+ Recovery

0

5

10

15

20

25

30

2005 2006 2007 2008 2009 2010 2011 2012 2013

CAGR 08-13

Petabytes 234.8 719.9 1,992 4,513 6,336 11,270 22,565 42,730 76,253 76.0%

Bit Growth 258% 207% 177% 127% 40% 78% 98% 90% 80%

Reve

nu

e

(Bil

lio

ns o

f D

olla

rs)

14.8%-14.8%

12.8%

21.9%

70.6%

25.8%

CAGR

08-13

ASP 1GB eqv. 52.1 19.1 7.94 2.99 2.40 1.65 1.03 0.61 0.35 -35.0%

ASP Change -52.3% -63.3% -58.5% -62.4% -19.7% -31.5% -37.2% -40.6% -43.3%

Source: Preliminary Gartner, November 2009

Semiconductor Forecast Worldwide--Forecast Database [SEQS-WW-DB-DATA]

NAND Revenue

12.4%

12.5%

1.2%

Pricing Could

be More

Conservative!

8

NAND Flash Demand Drivers: Mobile and SSD are Vital

Imaging Video & ComputingAudioDataThousands

of PB

19.9 PB

76,253 PB

Note: NAND flash consumption includes both in-system and removable storage such as flash cards.

Source: Gartner November, 2009

Semiconductor Forecast Worldwide--Forecast Database [SEQS-WW-DB-DATA]

Lifestyle Storage

Driver

Criteria

- Units (M)

- Capacity (GB)

- Portable

- Durable

- Power

- Performance

-

20,000

40,000

60,000

80,000

100,000

2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013

Digital Camera

Media Player

USB Drive

Camcorder

Mobile Phone

Gaming

Computing

Automotive

Other

9

The Most Exciting Time

iPhone/SmartPhones/Droids/Tablet

= New PC

Thin Is In, No HD

10

Flash Is Everywhere Already

In the next decade, it

will be BIGGER than

you think!

11

Huge Investment and Commitment: Not for the Faint of the Heart

Fab1

Fab2

Fab3

Fab4

Fab5

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

13

Fundamental NAND Flash Cell

Operation

• Write and Erase by Fowler-Nordheim tunneling

– High write (program) and erase voltage needed, >20V

14

NAND Read Operation

Vread

Vcgrx (0V for Bin)

Vread

Vread

0V

WL0

WL1

WL2

WL30

WL29

WL31

SGD

WL31

SGS

SGD

CSL

BL0 BL1 BL3BL2

Blo

ck n

Floating

0V

Vread (5V)

Vread

Vread

Vread

• 8KByte bit-lines are read at a time.

•Block n is the selected block.

•WL1 is the selected wordline.

•Vread turns on all the un-selected

cells, regardless of its data.

•Read current flows through erased

(or data 1) cell.

15

NAND Program Operation

• 8KByte bit-lines are pgm at a time.

•Block n is the selected block.

•WL1 is the selected wordline.

•BL 2 is the program bitline

•BL 1 and 3 are program inhibited

•Example here is SB (Self-Boosting)

•Vpgm step up, so does Vpass

• Data=1 cells in WL1 is program

disturbed

• Data=1 cells on BL 2 is programmed

disturbed

• All other cells are Vpass disturbed

Vpass

Vpgm (~20V)

Vpass

0V

Vdd

WL0

WL1

WL2

WL30

WL29

WL31

SGD

WL15

SGS

SGD

CSL

BL0 BL1 BL3BL2

Blo

ck n

Floating

0V

Vdd

Vpass (9V)

Vpass

Vpass

Vdd Vdd0V

16

x416 levels

SLC2 levels

MLC4 levels

What Is MLC (Multi_Level_Cell) NAND

3 bits/cell8 levels

1

1

1

1

0

0

0

0

0

0

1

0

0 1

00 01 10 11

0

0

1

1

0

1

0

0

0

1

0

1

0

1

1

0

0

1

1

1

1

0

0

0

1

0

0

1

1

0

1

0

1

0

1

1

1

1

0

0

1

1

1

0

1

1

0

1

0

0

0

1

000 001 010 011 100 101 110 111Co

st

Go

es D

ow

n

Syste

m E

xp

ert

ise

Incre

asin

gly

Im

po

rtan

t

17

Key Attributes of NAND Flash MemoryMaking it the Driver of Ubiquitous Portable Storage Mega Markets

• Lowest Cost– Simplest cell structure

– Smallest cell with SA-STI (4F2), close to litho defined minimum

– 2F2 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 (200us), 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.

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

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-30nm 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!

20

Flash Management Know-How Required

Self Monitoring &

reporting

S.M.A.R.T

Likelihood of Flash

Wear Depends on Use

Dynamic Wear-Leveling

Manufacturing/Accumulated

Bad Blocks

Bad-Block Management

Bit Flips

Error Detection/

Error Correction

Write/Erase

Cycles Limitation

Static

Wear-Leveling

Limited Data Retention

Active Data Refresh

Challenge increases as process shrinks

21

The building

blocks make

the difference!

Advantage of Vertical Integration

22

Conclusions

• Amazing Journey the Last 20 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

23

PersonalData Storage

Core

DigitalImaging

Shoot & Store™ Family

Blue Family

SanDisk Ultra® Family

SanDisk Extreme® Family

Best

Good

Better

MobilePhones

Memory Stick PRO Duo™

miniSD™

MMCmobile™

microSD™

iNAND™

DigitalAudio

Sansa® e100

SansaTM m200

SansaTM c100

SansaTMe200

Gaming

SD™

Memory StickPRO Duo™

Cruzer Crossfire™

Cruzer® Mini

Cruzer® Micro Skins

Cruzer® Titanium II

Cruzer® Micro II

Thank You! NAND Everywhere…