Greatest challenges of the 21st Century:

To create computing capability that can operate with THz speed with Terabits/cm2 information storage, and to apply this technology in biotechnology, business, and education

•Speed drives technology

•Technology drives society

“Terascale electronics---endless quest for IC speed”

Toh-Ming Lu

lut@rpi.edu; www.rpi.edu/~lut

Director

Center for Advanced Interconnect Science and Technology

(RPI, SUNY-Albany, MIT, UT-Austin, N. Texas, Texas Tech., Cornell, UC Berkeley, Columbia, Georgia Tech, Rochester, U. of Maryland)

Outline•End of scaling

•Systems technologies: on-chip/off-chip interconnect

•Nanoelectronics

Information age?

Execution, storage, and transmission of massive information

What technology drives the information age?

Hardware in Computer:

Chips, hard drives, display…….

-----Microelectronics technology

Technology for Information age--------Microelectronics

Electronics industry: driving force of the information age.

largest manufacturing industry in the United States and in the developed world

Over ~14% per year growth in the last 30 years --- continue to grow in the next few decades

Will need a continuing supply of BS, MS, and Ph.D

Who are chip makers?

•Intel, IBM, Motorola, AMD, DEC, LSI Logic, National Semiconductor, Lucent, TI, HP…..

•DELL, Compaq, Gateway…don’t make chips!

History

Invention of solid state electronics (40’s)--------The transistors

Then ICThen Mainframe (60’s)----execution and

storageThen PC (70’s)----execution and storageThen PC plus internet plus WWW-----execution, storage, and transmission

Why so exciting?

• Intellectually stimulating

• Impact: changes the society in major way– Business: creates enormous wealth – Education: fundamentally change the way

we learn– Medicine: will change the way we treat

diseases

“Turmoil and opportunities at the dawn of the 21st Century---the road of an academic department in higher education”

(Toh-Ming Lu, amazon.com, 2000)

Computer logic---a series of on and off operation (clicks)

Imaging a super fast telegraph!(1GHz: 1000 million clicks per second; 1THz = 1000GHz)

“Fast” means: more clicks per second

The narrower the “click” the faster you get

The shorter the device the narrower the click

time

MOSFET Transistor

Key questions in the industry

Technical:

---Is there an end to increase IC speed?

Business:

---Is there a market for super fast ICs?

Some key technological challenges

---Limit on device dimension

---Limit on interconnect speed

•Intel: 1 THz FET, 25nm channel length

•IBM: 210 GHz HBT, base 100 atoms

Recent news:

metal

Limits on patterning: diffraction

resist

Limit on RC delay

Chip cross section

Interconnect (RC) delay

Through wires

To avoid overlapping

Reduce the number of “clicks” per second ---separate the “clicks” apart

Therefore reduce the speed

time time

“Terascale electronics---endless quest for IC speed”

Toh-Ming Lu

lut@rpi.edu; www.rpi.edu/~lut

Director

Center for Advanced Interconnect Science and Technology

(RPI, SUNY-Albany, MIT, UT-Austin, N. Texas, Texas Tech., Cornell, UC Berkeley, Columbia, Georgia Tech, Rochester, U. of Maryland)

Outline•End of scaling

•Systems technologies: on-chip/off-chip interconnect

•Nanoelectronics

----Shorter wires, higher density, more functionalility

—Beyond RoadmapBeyond Roadmap

Mitsubishi Electronics America: ADVANCED PACKAGING June/July 2000 issue.

High bandwidth:to optoelectronics

systems (THz)

Heat extractors

I/O, passives, power

Logic layers

A/D, sensors, IP cores

memory

?

PC, communications,internect…

3D heterogeneous systems: bonding, alignment, via etching/filling

GaAs/Si?--killer tech

Opportunities for more Si mainstream technologies:

---Decades beyond the Roadmap

Stacked chip assemblies (logic, memories, interposer for passives);

Heterogeneous systems for sensors and MEMS;

Hard IP core-based SOC designs (including mixed signal);

High speed processors;

LAN architectures (for wireless applications and/or for multiplexed interconnects).

Gutmann et al (2001)

Pictorial Representation of 3D Integration Conceptusing Wafer Bonding,

* Figure adapted from IBM Corporation and used with permission.

Via Plug

Second Level(Thinned Substrate)

First Level

Third Level(Thinned Substrate)

Via Bridge

Bond

DeviceSurface

DeviceSurface

Bond(Face-to-face)

(Face-to-back)

DeviceSurface

Substrate

Substrate

Substrate

J. Lu et al

•Processing issues: bonding-alignmentthrough wafer via etchingbarrier and metallization

•Reliability:thermo and mechanical stabilityelectromigrationheat extraction

Broad band interconnect technology---high speed data transfer

Replacing electrical connection by optics:•Modulators/switches: electro-optic, optic-optic•Optical waveguides•Data compression (software)

Modulators guide

Chip stack

switches

fiber

Or: wireless!

light

from THz source: A

modulating signal: B

read out: C

Mach-Zehnder Ring

B C

0101

0011

0001

A

AB

Cheterostructurelayer

substrate

d

R. Kersting, G. Stasser, and K. Unterrainer, Terahertz phase modulator, Electr. Lett., 36, 1156 (2000)

Electro-optic modulator

Electrical signal

Nonlinear EO

Modulated light

light

Optical switches: •MEMS---mirror switches: D. Bishop et al, Physics Today Oct 2001 (Lucent)•Nanotube switches: Zao et al (2001)---THz speed•Quantum dots switches: Dutta et al (2001)---THz speed

MEMS

Potentially viable optical interconnect schemes—Dr. Persans

waveguide

CMOS circuits and metallization

optoelectronic transceivers

• Bump-bond optoelectronic chip on top of complete CMOS package

• Grow optoelectronic components monolithically; local microphotonic waveguides grown and patterned; polymer waveguide layers for off-chip and longer distance

• Monolithic optoelectronic components; incorporate longer waveguides into metal interconnect package

• Use waveguides within sensor-chip or system-on-a-chip paradigm

waveguide

metal or multilayer dielectric mirror

via

cladding

receiver

Agarwal, Ponoth, Plawsky, Persans: Appl. Phys. Lett. 78, 2294 (2001)

Mainstream computer/communication technology:

•Strong industrial/State/Federal partner support•Enormous employment opportunities•Decades of growth---expected more growth in decades

End of device scaling does not imply end of Si technologies!

Emerging technologies

•Nano-scale electronics: very rich and unexplored science•Strong Government support•Long term benefits (not likely mainstream computing

in at least 20 years)

---The greatest and immediate impact may not be in electronics, but in biomedical applications

“Terascale electronics---endless quest for IC speed”

Toh-Ming Lu

lut@rpi.edu; www.rpi.edu/~lut

Director

Center for Advanced Interconnect Science and Technology

(RPI, SUNY-Albany, MIT, UT-Austin, N. Texas, Texas Tech., Cornell, UC Berkeley, Columbia, Georgia Tech, Rochester, U. of Maryland)

Outline•End of scaling

•Systems technologies: on-chip/off-chip interconnect

•Nanoelectronics

Interconnects via Terahertz

• ULSI chip divided in tiles • Communicate via plasma wave electronics receiver-transmitter pairs

Michael S. Shurhttp://nina.ecse.rpi.edu/shur/

Receiver-transmitter pairs

Source Drain

Gate2Delectronfluid

GateInsulator

Ug

Plasma wave

Deep sub-0.1

Smalley group (2001)

Room temperature single electrontransistor using nanotube

Oriented & interconnected nanotube networks—Ajayan et al

– Local modification and Junction formation

– Termination (cutting of structures)

Catalyst

Junctions

Focused Ions

Fantastic opportunities in applied and basic science research

Examples:

New materials synthesis: polymers; nitrides, carbidesNovel polymer-metal, polymer-cermic, polymer-polymer composites:Novel phase separation, crystallization, dynamic growth phenomenaNovel interfacial diffusion, reactions, and transformationsNovel nano-structure science; light emitting nano semiconductorsNovel non-linear thin film materials; high electro-optic coefficient materialsNovel opto-electronics materials, layered structuresQuantum effect on narrow linesMaterials response under extreme speed and frequencyReal time atomic scale microscopies

glas

s pl

ate

Nano-Si or nano-C layer

THz gratinghelps coupling

reference chip sample chip

THz Bio-Chip for Sensitive Detection

THz signature or fingerprint of genetic materials: DNA, RNA or Protein attach to nano-layer in sample chip, from 10 GHz to 10 THz frequency range. (Zhang, Kersting)

THz wave

On-Chip

Interconnect

3-Dimensional

Interconnect

3D Chips

Microsystems

•Non-Electronic Chips

•Scalable Systems

Yesterday

Today

Tomorrow“Norton” Facility

(IC Laboratory) 5”-8” 2µ CMOS

MCR(Wafer Processing

R&D) 8” State-of-the-Art Wafer Fab

Terascaleelectronics?Bio-devices?

•Welcome students doing PhD at Rensselaer

•Welcome visiting scholars and collaboration

Electrical Storages

•Memory:Trenches/Stacked capacitors

•Passives capacitors

Magnetic storage---towards terabits/in2

C. Ross, Annu. Rev. Mater. Res. 2001. 31:203-235.

Three strategies:

• exchange-decoupled grains (conventional)•In-plane patterned media•Perpendicular patterned media

Limits on magnetization:---Nayak/Wang/Korniss (Physics)

P

H

P

H

?

Molecular memories:Materials Today(Feb 2002)