microcontact printing copyright © 2012 board of trustees, university of illinois. all rights...

Microcontact Printing

Copyright © 2012 Board of Trustees, University of Illinois. All rights reserved.

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Objective

You will:

• become familiar with techniques used in nanotechnology.

• design and make a stamp for patterning a silver surface.

• pattern a silver surface by stamping a single layer of molecules onto it.

• test the properties of the patterned silver surface.

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Motivation

• Printing large area electronic devices--such as wide-screen televisions.

• Printing these electronic devices on flexible materials like plastic.

• Microcontact printing can pattern large area electronic devices on flexible materials at a low cost.

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Nanotechnology Applications

Biosensors

Flexible Electronics

Printed Circuits

Electronic Paper

Definition

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Micro contact printing:

is a prefix that means one millionth.says that two objects are touching.takes place when a material like ink is transferred by the contact.

transfers ink in a very small pattern from a rubber stamp onto another surface.

Microcontact printing:

1 m 1 mm 1 µm

Microcontact Printing Process

master

moldPDMS

polymerize, release

stamp

inker pad

ink solution

print

release

etch

silver substrate

SAM

ink

Making a Stamp

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Transparency Mold

Molded PDMS

Master Image

Patterning a Silver Surface

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Thin Silver SurfaceProtective “Ink” Layer

Molded PDMS Stamp

Protective “Ink” Layer

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1-hexadecanethiol

PDMS Stamp

Sulfur (thiol)

Hexadecane

Silver Surface

Silver Etchant Protected Regions

Soft Lithography

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Silicon Wafer Silicon WaferSpin Coat Photoresist

Spin Coat Photoresist

Transparency Master

Transparency Master

Ultraviolet LightUltraviolet Light

Developer: Remove unexposedphotoresist

Developer: Remove unexposedphotoresist

Cure PDMS

Etch Silicon

Inker Pad Silicon Wafer (or other substrate)

InkStamp

EtchFinished Product

Finished Product

Soft Lithography

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Silicon Wafer

Silicon Wafer (or other substrate)

InkStamp

Spin Coat Photoresist

Transparency Master

Etch

Ultraviolet Light

Finished Product

Developer: Remove unexposedphotoresist

Etch Silicon

Finished Product

Microcontact Printing Press

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Today’s Activity

1. Ink Stamp2. Stamp silver3. Etch silver4. Observe pattern5. Silver glass