1

Silicon Microchannel Cooling.. and related

microfluidic and microcoolingtopics

Han GardeniersMESA+ Research Institute -University of Twente, NL

20th January 2003

Outline

• short overview MESA• short overview BIOS / Lab-on-a-Chip• buried microchannels:

– micromachining process– silicon nitride and polysilicon– applications: pipette for mechanical DNA study

• cryogenic microcooler project overview

2

MESA+ Research InstituteOrganisational Overview

3

Chem. Eng.: Chemical Analysis (CA) Inorganic Materials Science (IMS) Materials Science and Technology of Polymers (MTP) Supra Molecular Chemistry and Technology (SMCT)

Electr. Eng.: Biosensors / Lab-on-a-Chip (BIOS)Semiconductor Components (SC)Computer Architecture, Design & Test for Embedded Systems (CADTES)Integrated Circuit Design (ICD) Systems and Materials for Information Storage (SMI)*Lightwave Devices (LDG)*Transducers Science and Technology (TST)

Appl.Phys.: Biophysical Techniques (BFT) Computational Materials Science (CMS) Systems and Materials for Information Storage (SMI)*Lightwave Devices (LDG)*Low Temperature Physics (LT) Optical Techniques (OT) Solid State Physics (VSF) Complex Photonic Systems (COPS)

Appl. Math.: Applied Analysis and Mathematical Physics (AAMP)

MESA+ Research Groups

Micro and nanofluidicdevices for chemical and biomedical applications

Current researchBIOS Lab-on-a-Chip group

Han GardeniersMESA+ Research Institute -University of Twente, NL

(also with Micronit Microfluidics B.V.)

1st November 2002

4

Development of µTAS/LOC concept

1970

1980

1990

2000 and beyond:Lab-on-a-Chip

5

Lab-on-a-Chip: motivation

General reasons for miniaturisation:• Reduced weight (portable)• Reduced size (implantable, integratable)• Reduced price (batch fabrication, disposable)• Reduced consumption of chemicals (expensive or limited source)• Reduced energy consumption• Reduced production of waste (toxic products)• Reduced flow (accurate dosing)• Increased heat exchange• Fast mass transport• Integration of sensors• Parallellisation• Automation

Micro Flow Injection Analysis System for Ammonia determination

from: Ph.D. thesis Theo Veenstra

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Measurements modular system

R.M. Tiggelaar et al., Sens. & Act. B in press

Hydrodynamic chromatography chip

Separation is enhanced by smaller channel height

Mass M1

Mass M2

0.9

0.92

0.94

0.96

0.98

1

0 10 20 30 40 50 60

Reff (nm)

Rel

ativ

e re

tent

ion

10 ? m channel

1 ? m channel

Anal. Chem. 74, 2002, p. 3470-3475, Sens. & Act. B 82 (2002) pp. 111-116

from: Ph.D. thesis Marko Blom

Separation of 26, 44, 110, 180 nmfluorescent polystyrene particles and a marker

7

Silicon micromachined hollow microneedles for trandermal liquid transport

Epidermis

Dermis

Diagnosticsensor ordrugcontainer

Hollow microneedles

20 ?m

Fabricationprocessout-of-planeneedles

DRIE etch

KOH etch

1

2

3

4

5

c

d

Si{111}

Proc. MEMS 2002, pp. 141-146; submitted J. MEMS

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Resulting microneedles

Application of Sodium Diclofenac to rats

0

100

200

300

400

500

600

700

800

Dic

lofe

nac

plas

ma

Leve

ls,

Drug plasma concentrations obtained after 6-hrapplications of increasing number of microneedles

Diffusion process withoutneedles

350 micron, 16 needles

350 micron, 36 needles

350 micron, 81 needles

ng

/mL

Microneedle array type Courtesy of NanoPass Ltd.

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Microsystem for lithium therapy monitoring

work of: Elwin Vrouwe and Regina Luttge

glass chip for capillary electrophoresiswith end-column integratedconductivity detection

close-up of platinum electrodesintegrated at end of

electrophoresis microchannel

Sample

PDMS

High Voltage

Injector Chamber to Separation Buffer

CE “ Sensor Chip”

Si-needle array chip clamped on top of sample vial “Blood Sampler”

Time / sec

Li+Na+

K+

Calibration

Sample intakethrough needles

C ond

uctiv

it y a

.u.

Work of: Regina Luttge

Silicon microneedles + CE chip

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Buried microchannelsin silicon

SEE PRESENTATION PART 1

Mechanical measurements on DNA

Capture bead Place bead on pipette Capture bead

Capture DNA Stretch DNA

11

-100

10

2030

40

5060

70

80

0,6 0,8 1 1,2 1,4 1,6 1,8

Relative extension

Fo

rce

(pN

)

stretching

relaxing

entropic effects

spring-like

conformational effects

Two beads, one gripped by amicromachined pipette and the other by optical tweezers, with a DNA molecule (not observable) in between

(a) no force applied

(b) 30pN force applied

Stretching of? -phage DNA

Miniaturizedcryocooler

Johannes BurgerJohannes Burger, Han van Egmond, Harry Holland, , Han van Egmond, Harry Holland, Han Gardeniers, Marcel ter Brake and Miko ElwenspoekHan Gardeniers, Marcel ter Brake and Miko Elwenspoek

MESAMESA++ Research Institute, University of Twente, The NetherlandsResearch Institute, University of Twente, The Netherlands

Financial support: Financial support: Dutch Foundation for Technological Research (STW)Dutch Foundation for Technological Research (STW)Project TTN.3100 “Microcooling”Project TTN.3100 “Microcooling”

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Gas-gapheatswitch with pressure controller

Sorption compressorcell with heater

Checkvalveunit

Aftercooler

So

rption

com

pres

sor u

nit

T environment

Q

Counterflow heatexchanger 1

Throttlevalveand cryostat

Co

ld s

tage

Refrigeration load

Insulating vacuumhousing

Counterflow heatexchanger 2

CondenserTE-cooler

Heat-sink

Heat-sink

300 K

300-600K15 W

0.1 -2 MPa

244K2.1 W input

0.4 W cooling

165K0.4 W

Xenon5 mg/s

MicroCooler

Micromachined check valves

Sieve

Boss

Wafer 1

Wafer 2

Wafer 3

Wafer 4

Input glass tube(glued)

Output glass tube(glued)

Spring

Top view Top view

Valve seat

J.F. Burger e.a., Proc. MEMS 1999

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Cold stage structures on 4-inch silicon wafer

J.F. Burger e.a., Proc. MEMS 2001

Micro cold stage

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Micro cold stage fabrication

Integrated cold stage

J.F. Burger e.a., MEMS 2001

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Glued capillary-to-chip connection

sintered filter

thermocouple/heater

activated carbon

support for thermocouple

gas supply tube

suspension of inner cell

ZrNi thin-film hydrogenactuator

10

cm

10 mm

‘splitter’ of gas supply tubeand thermocouple

inner cylinder (150 mwall thickness)

?

gas-gap heat switch

cro

ss s

ectio

n

Compressor design

16

1

1

Filter 2 micrometerFilter

Sorber

Innercontainer

with heater

Gas-gap

Inletoutlet

Sorber cellSorber cell

Compressor test set-up

mp2p1

gassupply pump

compressor cell

valve

metering valve

safety valvepressure sensor

flow sensor T2T1

P2P1

Tambient

heater power

temp.

gas gap

gas-gapcontrol

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Compressor flow test

0

100

200

300

40 45 50 55 60 65 70 75 80

T (

C) T1

T2

0

4

8

12

16

40 45 50 55 60 65 70 75 80

p (b

ar) p1

p2

0

5

10

15

20

40 50 60 70 80time (min)

flo

w (

mg

/s)

-2

mflow

valve

open

closed

Thermal switches: mechanical example

T. Slater e.a. Techn. Digest Transducers 95, Stockholm

C. Baert e.a. (MME 94, Pisa)

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Gas gap heat switch with hydrogen (1)

J.F. Burger e.a., Thermodynamic considerations on a microminiature sorption cooler, Cryocoolers 10, Kluwer Academic / Plenum Press, New York, 1999, p. 553

0.1

1

10

100

1000

10000

0.1 1 10 100 1000 10000 100000pressure (Pa)

measurements, gap = 0.3 mm

0.03 mm

0.3 mm

3 mm

Gas gap heat switch with hydrogen (2)

J.F. Burger e.a., Thermodynamic considerations on a microminiature sorption cooler, Cryocoolers 10, Kluwer Academic / Plenum Press, New York, 1999, p. 553

Requirements heat switch:

• low pressure < 0.5 Pa• ON-OFF pressure ratio > 50*• switching times < 30 sec• actuation power < 0.2 W• lifetime > 106 cycles

*limiting ON-OFF ratio ? 150 (mm) / gap width = 500 for gap of 300 ?m

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Metal hydrides

Van ‘t Hoff plots forseveral metal hydrides

Metal hydrides: phase transition

Absorption and desorption lines for one isotherm

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ZrNi-H

Experimental data for the ??? and ? ?? phase changes of ZrNi-HW. Luo e.a., J. Less-Common Metals 162, 1990, p.251

ZrNi films for reversible H2 pressure actuation

To be presented at Actuator 2000

Why films?• Sputtered films offer possibilities for integration

with e.g. heater elements• Passivation with Pd film possible

(bulk ZrNi is very sensitive to oxygen)• Thin films offer faster hydrogen pressure switching

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To be presented at Actuator 2000

0.0001

0.001

0.01

0.1

1

10

0 0.2 0.4 0.6 0.8 1 1.2

H/ZrNi

Pre

ssu

re (

mb

ar)

2202001801601401201008060

Temperature:

ZrNi films: Experimental results (1)

Gardeniers e.a., Proc. AKTUATOR 2000

To be presented at Actuator 2000

ZrNi films: Experimental results (2)

TEM pictures of ZrNi-Pd film before (left) and after (right)several thousands of absorption cycles

Gardeniers e.a., Proc. AKTUATOR 2000

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To be presented at Actuator 2000

0.0001

0.001

0.01

0.1

1

10

0 5000 10000 15000 20000 25000 30000Time (s)

Pre

ssur

e (m

bar)

60 oC

230 oC

ZrNi films: Experimental results (3)

Gardeniers e.a., Proc. AKTUATOR 2000

Obtained pressure swing: 0.03 Pa - 125 Pa

0

0.2

0.4

0.6

0.8

1

1.2

0 10 20 30 40 50time (s)

Pre

ssu

re (

mb

ar)

T=60

T=80

T=100

T=120

T=140

ZrNi films: Experimental results (4)

Gardeniers e.a., Proc. AKTUATOR 2000

Obtained switching times: less than 60 secs.

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Acknowledgements

• Stichting Technische Wetenschappen (Dutch Technology Foundation) & NanoPass Ltd.

• MESA+ clean room staff for technical support