Biomedical Engineering Reference
In-Depth Information
12
Electron Beam Lithography for
Biological
Applications
John G. Hartley
CONTENTS
12.1. Introduction......................................................................................................................... 259
12.2. History.and.Overview.of.Lithography........................................................................... 261
12.3. Basics.of.Electron.Beam.Lithography.............................................................................. 262
12.3.1. Resist......................................................................................................................... 263
12.3.2. Cost........................................................................................................................... 264
12.3.3. Imaging.................................................................................................................... 265
12.3.3.1. Tone.Selection........................................................................................... 265
12.3.3.2. Resolution................................................................................................. 266
12.3.3.3. Spot.Size,.Corner.Radius,.and.Line.Edge.Roughness........................ 267
12.3.3.4. Etch.Resistance......................................................................................... 267
12.3.4. Image.Placement.and.Overlay.............................................................................. 268
12.3.5. Defects...................................................................................................................... 268
12.4. Conclusions.and.Perspectives.......................................................................................... 269
References..................................................................................................................................... 270
12.1 Introduction
Biological.processes.are.intrinsically.a.“bottom-up”.fabrication.process.where.molecular.
machinery.either.self-replicates.(viruses,.bacteria,.and.single-celled.organisms),.or.in.the.
case.of.multicelled.organisms.replicate.and.differentiate..At.this.point.in.time,.our.ability.
to.build.these.molecular.machines.by.design.is.still.in.its.infancy.and.mostly.consists.of.
small. perturbations. of. patterns. found. in. nature. or. intentional. replication. (Benner. and.
Sismour,.2005).
The. semiconductor. industry,. by. contrast,. relies. heavily. on. a. “top-down”. fabrication.
technology.to.build.nanoscale.structures.that,.while.rivaling.simple.biological.systems.in.
complexity,.lack.self-replication.capability.and.are.in.no.sense.alive..The.ability.to.pattern.
at.the.nanoscale.has.enabled.a.variety.of.novel.tools.for.the.investigation,.manipulation,.
and.diagnostics.of.biological.processes.
One. of. the. more. common. applications. of. top-down. lithographic. techniques. in. the.
biological. application. space. is. patterned. functionalization. (Christman. et. al.,. 2008,.
2009;. Glezos. et. al.,. 2002;. Harnett. et. al.,. 2000;. Kolodziej. et. al.,. 2011,. 2012;. Kolodziej. and.
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