53 lucent advanced mems slm for communications imaging and

7/30/2019 53 Lucent Advanced MEMS SLM for Communications Imaging and

1/17

ADVANCED MEMS SPATIAL LIGHT

MODULATOR FOR COMMUNICATIONS,IMAGING, AND TARGETING

Microsystems and Nanotechnolgy ResearchBell Labs Lucent Technologies

Murray Hill, NJ

Warren Lai, C.S. Pai, Fred Klemens, John Miner, Ray Cirelli, Ed Ferry, Ashley Taylor,Tom Sorsh, Avi Kornblit , Bill Mansfield, Eric Bower, Bob Fullowan

Rae McLellan, Nagesh Basavanhally, Dave RamseyMara Elina Simon, Vladimir Aksyuk, Cristian Bolle, Csar Chialvo, Harold Dyson, ArmanGasparyan, Susanne Arney

This material is based on work supported in partby DARPAs CCIT program under contract NumberHR0011-04-C-0048


2/17

Optical, secure, free-spacecommunications

Advanced pixelated SLMs:Applications

Imaging Complex Mirror Array

LARGE Tip-tilt, Piston motionFAST Tip-tilt, Piston response time.

FLAT, smooth, reflectiveHIGH Fill factor

Collimating optics

SLM

Wavefront Sensor

camera

control

* Reference starWith AO Without AO

Segmented: Trackingtargetingscanning


3/17

Breaking out of the traditional MEMS spaceMEMS arrays complexity map

Actuator density

Array

Linear

2D

120 m mirror (system,chips size) Integrable with electronics,scalable ( 100V) 642, 2562 and beyond High fill factor (>98%) Flat (30nm, 2nm Roughness)

Large Mechanical Power

-3 m x2 ( -3

2 )

Fast Large displacement

Flat (thick) mirror

100

101

102

103

104

105

10-3

10-2

10-1

100

101

102

103

104

105

Polychromator

BostonMM

Lucent CCIT SLM

Si Light Machines GLV

IBM Millipede

Lucent LRouter

Lucent WSS

Early DMD

Lucent M

Micronics

TI DMD

TT 2D

MARS

IRIS

MEMEXEXC

C

OMPLEXITY

Mechani

calPower/D

OF(nanowat

ts)

DOF / mm2

(1/mm2)

R ~ Log (Array Size * bits/pix) Goal


4/17

Design principleDual, in-plane, rotational comb-drives

arm / springlayer

V=0

V

In-plane

combs

Routing

layer

Combs side view

4 actuators in parallel One control signal per actuator

2 comb drives per actuator

Piston motion results from

two opposite actuators or all fouractuators together


5/17

Design principleDual, in-plane, rotational comb-drives

arm / springlayer

V=0

V

In-plane

combs

Routing

layer

Combs side view

4 actuators in parallel One control signal per actuator

2 comb drives per actuator

Tilt motion results from

single actuators or two adjacentactuators together


6/17

Design principle andfabrication

In-planecombs

V=0

V

arm / springlayer

Routinglayer

Combs side view

Combs front viewTotal: 17-28 mwith 100nm registration accuracy between all layers

1-2 m PolySi-3 Mirror CD .5 m

1-2 m PolySi-2 Spring/Arm CD .5 m

6-12 m PolySi-1 Combs CD .5 m

2.5 m Routing (PolySi-0 +) CD .5 m

2-4.5 m Sacrificial layers (each)

20


7/17

SE

MI

mag

es10 mask levels 248nm4X stepper lithography

Reinforcing struts (back of the mirror)

120 m


8/17

Mono

lithicM

irror

Strut-reinforced, 1.5 mthick mirror with

40 Ti / 400 Au

Excluding thatregion and the

overall curvature theRMS roughness is~1.85nm

Mirror, front side

Even with thisdeposition/polishingartifact the peak tovalley variation is

~50nm


9/17

Test Vehicle

CORE

PERIPHERY

(A)

(B)(C)

Packaged 64x64 256x256 on 8 wafer


10/17

0 10 20 30 40 50 60 70 80 90 100 110

0

1

2

3

4

5

6

displcement(m)

angle(degrees)

Voltage (V)

1AT

2AT

4AP

Mechanical Response: Angle-Piston vs. Voltage

2-Actuator Tilt

1-Actuator Tilt

4-Actuator Piston12

34

Continuous, smoothvarying, stable,controllable Motion


11/17

Combined X-tilt and Piston:

0 1 2 3 4 5 6-5

0

5

Piston motion (um)

Tiltangle

()

X-tilt

Y-tilt

1

23

V1=V2 in range 0 to 80V (SQRT spaced)V3=V4 in range 0 to 80V (SQRT spaced)

+/-0.1 degrees totalaccumulated Y-tilt(open loop)

4


12/17

0 1 2 3 4 50

1

2

3

4

Combined Diagonal Tilt and Piston:

Piston motion (um)

X-tilt

Y-tilt

Tiltangle

()

1

23

V1=V3 in range 0 to 80V (SQRT spaced)V2 in range 0 to 100V (SQRT spaced)

V4=0

4

V4 > 0


13/17

5 10 15 20 25 30 35 40

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

Normalized

Amplitude

Frequency (KHz)

Mode F0

Tilt 1 29.6KHz

Tilt 2 29.6KHz

Piston 30.9KHz

next mode 140KHz

Mechanical Response: Resonance

2-Actuator Tilt

1-Actuator Tilt

4-Actuator Piston

Simulated Resonancefrequencies in Vacuum F0~30Kz from fitting

Polytec Vibrometer Measurement


14/17

-20 0 20 40 60 80 100 120 140 160 180 200 220

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

P

iston(m)

time (s)

X-angleTilt(deg)

Pr=9.5s

Tr=23.4s

Pf =7.4s

Tf =18.6s

-20 0 20 40 60 80 100 120 140 160 180 200 220

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

-0.4

-0.2

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

P

iston(m)

time (s)

X-angleTilt(deg)

Pr=9.5s

Tr=23.4s

Pf =7.4s

Tf =18.6s

Atmospheric pressure,0-60V step

Me

chanic

alResp

onse:StepFun

ction

Interferometerstroboscopicmeasurement

Video frame rate:6000X slower thanactual motion


15/17

We have Implementedhigh-force actuatordesign in a 10-lithography-step MEMS

process

5.4m, 10s piston4.3, 20s tilt

MEMS fabricationapproach scalable to2562 and beyond

Integration-ready with

high-voltage electronics

Design andfabrication tour de

force100 101 102 103 104 105

10-3

10-2

10-1

100

101

102

103

104

105

Polychromator

BostonMM

Lucent CCIT SLM

Si Light Machines GLV

IBM Millipede

Lucent LRouter

Lucent WSS

Early DMD

Lucent M

Micronics

TI DMD

TT 2D

MARS

IRIS

MEMEX

LT CCIT TV

EXC

COMPLEXIT

Y

Mecha

nicalPower/

DOF(nanow

atts)

DOF / mm2

(1/mm2)

R ~ Log (Array Size * bits/pix)

Summary


16/17

Pure Tilt Dynamics

Time (us)

Pistonmo

tion(um)

Tiltangle()

X-tilt

Y-tilt

Piston

0 100 200 300 400-4

-3

-2

-1

0

1

2

3


17/17

8 inch

12um deep combs

Future: faster response

Deeper combs, stiffer springsDamping TuningTailor for different applications within this

platformContinue to work on integration / packaging

53 lucent advanced mems slm for communications imaging and

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