Nanoscale Electromolecular Lithography (NEL)

Wolfgang Borchardt

February 13, 2008

UC Berkeley, Mervin Ye Zhou 2Prof. Chang-Hasnain’s group

Short Introduction to NEL

New technique, proposed in 2005 by W. Shen, Y. Chen and Q. Pei (UCLA)

Nanoscale patterning of resists by using an electric mask mask: metal patterns on an insulative substrate (e.g. glass) Nanoscale metal patterns fabricated by e-beam and optical

lithography or self-assembly electrochemical polymerization in a water solution with 0.2

M pyrrole monomers and 0.15 M KCl voltage pulse with an amplitude of +1.0 V and a duration of

60 s

Wolfgang Borchardt

Sources:• NSF Nanoscale Science and Engineering Grantees Conference, Dec 12-15, 2005

Nanoscale Electromolecular Lithography (NEL) by Yong Chen… APPLIED PHYSICS LETTERS 87, 124106 2005

Electric lithography by electrochemical polymerization by W. Shen,Y. Chen and Q. Pei, UCLA

UC Berkeley, Mervin Ye Zhou 3Prof. Chang-Hasnain’s group

1st step

Wolfgang Borchardt

Mask

Resist

Substrate

Electrode

Insulator

Electrode

UC Berkeley, Mervin Ye Zhou 4Prof. Chang-Hasnain’s group

2nd step

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Electrode

Insulator

Electrode

UC Berkeley, Mervin Ye Zhou 5Prof. Chang-Hasnain’s group

3rd step

Wolfgang Borchardt

UC Berkeley, Mervin Ye Zhou 6Prof. Chang-Hasnain’s group

4th step

Wolfgang Borchardt

UC Berkeley, Mervin Ye Zhou 7Prof. Chang-Hasnain’s group

Results

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b) Selectively transferred lines

a) Linearly patterned mask

c) AFM image: constant voltage applied with different durations

Left:

SEM image of nanowire patterns

Right:

AFM image of nano dot patterns

UC Berkeley, Mervin Ye Zhou 8Prof. Chang-Hasnain’s group

Sub-10nm resolution?

Two classes of resists

(1) Traditional Self-assembled monolayers (SAMs):

Reengineering: exposure of useful chemical functional groups topographical changes

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(2) Highly crosslinked 2D-arrays: self-assembled onto electrode surfaces into

simple patterns EC-field will break crosslinks „Carving out“ of nanometer-scale regions

UC Berkeley, Mervin Ye Zhou 9Prof. Chang-Hasnain’s group

Advantages / Disadvantages

+ High-throughput => mass production

+ Scalable

+ Reliable / robust

+ Reduced defect density and improved yield in comparison with the 3D mold and mechanical process used in nanoscale imprint lithography

- Low resolution (>300nm) until now

- Nobody else reporting on this topic

Wolfgang Borchardt

UC Berkeley, Mervin Ye Zhou 10Prof. Chang-Hasnain’s group

Questions

Wolfgang Borchardt