Nano-Lithography

345 Pages·2011·18.68 MB·English

Nano-Lithography
Nano-Lithography

Edited by
Stefan Landis
First published 2011 in Great Britain and the United States by ISTE Ltd and John Wiley & Sons, Inc.
Adapted and updated from La nanolithographie published 2010 in France by Hermes Science/Lavoisier
© LAVOISIER 2010
Apart from any fair dealing for the purposes of research or private study, or criticism or review, as
permitted under the Copyright, Designs and Patents Act 1988, this publication may only be reproduced,
stored or transmitted, in any form or by any means, with the prior permission in writing of the publishers,
or in the case of reprographic reproduction in accordance with the terms and licenses issued by the
CLA. Enquiries concerning reproduction outside these terms should be sent to the publishers at the
undermentioned address:
ISTE Ltd John Wiley & Sons, Inc.
27-37 St George’s Road 111 River Street
London SW19 4EU Hoboken, NJ 07030
UK USA
www.iste.co.uk www.wiley.com
© ISTE Ltd 2011

The rights of Stefan Landis to be identified as the author of this work have been asserted by him in
accordance with the Copyright, Designs and Patents Act 1988.
____________________________________________________________________________________
Library of Congress Cataloging-in-Publication Data

Nanolithography English
Nano-lithography / edited by Stefan Landis.
p. cm.
Includes bibliographical references and index.
ISBN 978-1-84821-211-4
1. Microlithography. 2. Nanotechnology. I. Landis, Stefan. II. Title.
TK7872.M3N3613 2011
621.3815'31--dc22
2010046516

British Library Cataloguing-in-Publication Data
A CIP record for this book is available from the British Library
ISBN 978-1-84821-211-4

Printed and bound in Great Britain by CPI Antony Rowe, Chippenham and Eastbourne.
Table of Contents
Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi
Jörge DE SOUSA NORONHA
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii
Michel BRILLOUËT
Chapter 1. X-ray Lithography: Fundamentals and Applications . . . . . . 1
Massimo TORMEN, Gianluca GRENCI, Benedetta MARMIROLI and
Filippo ROMANATO
1.1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2. The principle of X-ray lithography . . . . . . . . . . . . . . . . . . . . . . 5
1.2.1. The irradiation system for XRL . . . . . . . . . . . . . . . . . . . . . 7
1.2.2. Properties of synchrotron radiation . . . . . . . . . . . . . . . . . . . 9
1.2.3. High Resolution and Deep XRL . . . . . . . . . . . . . . . . . . . . . 12
1.2.4. Examples of X-ray lithography beamlines . . . . . . . . . . . . . . . 12
1.2.5. Scanner/stepper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
1.2.6. The mask . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
1.3. The physics of X-ray lithography . . . . . . . . . . . . . . . . . . . . . . . 25
1.3.1. How phase and intensity of X-rays are altered by interaction
with matter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
1.3.2. X-ray lithography as a shadow printing technique . . . . . . . . . . 27
1.3.3. X-ray absorption in a resist and physical mechanisms
involved in its exposure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
1.3.4. Physical model of electron energy loss in resists . . . . . . . . . . . 35
1.3.5. Diffraction effects in X-ray lithography. . . . . . . . . . . . . . . . . 40
1.3.6. Coherence of synchrotron radiation from bending
magnet devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
vi Nano-Lithography
1.3.7. Basic formulation of diffraction theory for a scalar field . . . . . . . 44
1.3.8. Rayleigh–Sommerfeld formulation of diffraction by a
planar screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
1.3.9. An example of diffraction effects: Poisson’s spot in X-ray
lithography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
1.4. Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
1.4.1. Optimal photon energy range for high resolution and
deep X-ray lithography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
1.4.2. Diffraction effects on proximity lithography . . . . . . . . . . . . . . 56
1.4.3. High resolution 3D nano structuring . . . . . . . . . . . . . . . . . . . 61
1.4.4. 3D polymer structures by combination of NanoImprint (NIL)
and X-ray lithography (XRL) . . . . . . . . . . . . . . . . . . . . . . . . . . 64
1.4.5. Micromachining and the LIGA process . . . . . . . . . . . . . . . . . 66
1.4.9. Micro-optical element for distance measurement . . . . . . . . . . . 77
1.5. Appendix 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
1.6. Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Chapter 2. NanoImprint Lithography . . . . . . . . . . . . . . . . . . . . . . . 87
Stefan LANDIS
2.1. From printing to NanoImprint . . . . . . . . . . . . . . . . . . . . . . . . . 87
2.2. A few words about NanoImprint . . . . . . . . . . . . . . . . . . . . . . . 90
2.3. The fabrication of the mold . . . . . . . . . . . . . . . . . . . . . . . . . . 96
2.4. Separating the mold and the resist after imprint: de-embossing . . . . . 100
2.4.1. The problem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
2.4.2. Adhesion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
2.4.3. Adhesion and physico-chemical surface properties . . . . . . . . . . 103
2.4.4. Surface treatment of the mold . . . . . . . . . . . . . . . . . . . . . . 107
2.4.5. Treatment of the resist . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
2.4.6. Characterization of the demolding process . . . . . . . . . . . . . . . 114
2.5. The residual layer problem in NanoImprint . . . . . . . . . . . . . . . . . 118
2.5.1. The residual layer: a NanoImprint specific issue . . . . . . . . . . . 118
2.5.2. Is the thickness of the residual layer predictable? . . . . . . . . . . . 120
2.5.3. How can the process impact the thickness of the residual
layer? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
2.6. Residual layer thickness measurement . . . . . . . . . . . . . . . . . . . . 132
2.6.1. Macro-scale approach: coherence between film color and
thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
2.6.2. Microscopic approach . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
Table of Contents vii
2.7. A few remarks on the mechanical behavior of molds and flow
properties of the nanoimprint process . . . . . . . . . . . . . . . . . . . . . . . 148
2.8. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
2.9. Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
Chapter 3. Lithography Techniques Using Scanning Probe
Microscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
Vincent BOUCHIAT
3.1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
3.2. Presentation of local-probe microscopes . . . . . . . . . . . . . . . . . . . 170
3.3. General principles of local-probe lithography techniques . . . . . . . . . 171
3.4. Classification of surface structuring techniques using
local-probe microscopes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173
3.4.1. Classification according to the physical nature of the
interaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174
3.4.2. Comparison with competing advanced lithography techniques . . . 176
3.4.3. Industrial development perspectives . . . . . . . . . . . . . . . . . . . 177
3.5. Lithographic techniques with polymer resist mask . . . . . . . . . . . . . 179
3.5.1. Electron beam exposure of resists by scanning probe
microscopes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
3.5.2. Development of a resist dedicated to AFM nano-lithography . . . . 182
3.5.3. Lithography using mechanical indentation . . . . . . . . . . . . . . . 184
3.6. Lithography techniques using oxidation-reduction interactions . . . . . 185
3.6.1. Direct fabrication by matter deposition induced by STM
microscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186
3.6.2. Local anodization under the AFM tip . . . . . . . . . . . . . . . . . . 188
3.7. “Passive” lithography techniques . . . . . . . . . . . . . . . . . . . . . . . 198
3.7.1. Dip-pen lithography . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
3.7.2. Alignment technique by means of a mechanical masking
(stencil mask) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
3.8. Conclusions and perspectives . . . . . . . . . . . . . . . . . . . . . . . . . 200
3.9. Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201
Chapter 4. Lithography and Manipulation Based on the Optical
Properties of Metal Nanostructures . . . . . . . . . . . . . . . . . . . . . . . . . 207
Renaud BACHELOT and Marianne CONSONNI
4.1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207
4.2. Surface plasmons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208
4.2.1. Definition of a volume plasmon . . . . . . . . . . . . . . . . . . . . . 208
viii Nano-Lithography
4.2.2. Delocalized surface plasmons . . . . . . . . . . . . . . . . . . . . . . 209
4.2.3. Localized surface plasmons . . . . . . . . . . . . . . . . . . . . . . . . 212
4.2.4. Application to lithography . . . . . . . . . . . . . . . . . . . . . . . . 216
4.3 Localized plasmon optical lithography . . . . . . . . . . . . . . . . . . . . 216
4.3.1. Near-field optical lithography by optical edge effect . . . . . . . . . 217
4.3.2. Use of nanoparticle resonances . . . . . . . . . . . . . . . . . . . . . . 220
4.4. Delocalized surface plasmon optical lithography. . . . . . . . . . . . . . 222
4.4.1. Coupling between nanostructures and delocalized surface
plasmons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
4.4.2. Surface plasmon launch and interferences . . . . . . . . . . . . . . . 224
4.5. Conclusions, discussions and perspectives . . . . . . . . . . . . . . . . . 225
4.6. Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
Chapter 5. Patterning with Self-Assembling Block Copolymers . . . . . . . 231
Karim AISSOU, Martin KOGELSCHATZ, Claire AGRAFFEIL, Alina PASCALE and
Thierry BARON
5.1. Block copolymers: a nano-lithography technique for tomorrow? . . . . 231
5.2. Controlling self-assembled block copolymer films . . . . . . . . . . . . 233
5.3. Technological applications of block copolymer films . . . . . . . . . . . 237
5.4. Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
Chapter 6. Metrology for Lithography . . . . . . . . . . . . . . . . . . . . . . . 249
Johann FOUCHER and Jérôme HAZART
6.1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249
6.2. The concept of CD in metrology . . . . . . . . . . . . . . . . . . . . . . . 250
6.2.1. CD measurement after a lithography stage: definitions . . . . . . . 250
6.2.2. What are the metrological needs during a lithography step? . . . . . 251
6.3. Scanning electron microscopy (SEM) . . . . . . . . . . . . . . . . . . . 254
6.3.1. SEM principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254
6.3.2. Matter–electron interaction . . . . . . . . . . . . . . . . . . . . . . . . 258
6.3.3. From signal to quantified measurement . . . . . . . . . . . . . . . . . 263
6.3.4. Provisional conclusion on scanning electron microscopy . . . . . . 266
6.4. 3D atomic force microscopy (AFM3D) . . . . . . . . . . . . . . . . . . 266
6.4.1. AFM principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
6.4.2. Three-dimensionnal AFM (AFM3D) special features . . . . . . . . 275
6.4.3. Provisional conclusion on AFM 3D . . . . . . . . . . . . . . . . . . . 286
6.5. Grating optical diffractometry (or scatterometry) . . . . . . . . . . . . 286
6.5.1. Principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287
Table of Contents ix
6.5.2. Example: ellipsometry characterization of post development
lithography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290
6.5.3. Pros and cons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296
6.5.4. Optical measurements analysis . . . . . . . . . . . . . . . . . . . . . . 297
6.5.5. Specificities of scatterometry for CD metrology . . . . . . . . . . . 305
6.5.6. Scatterometry implementation: R&D versus production . . . . . . . 307
6.5.7. New fields for scatterometry . . . . . . . . . . . . . . . . . . . . . . . 310
6.6. What is the most suitable technique for lithography? . . . . . . . . . . 310
6.6.1. Technique correlation . . . . . . . . . . . . . . . . . . . . . . . . . . . 313
6.6.2. Technique calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . 313
6.6.3. Process development . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314
6.6.4. Evaluation of morphological damage generated by the primary
electron beam from CD-SEM . . . . . . . . . . . . . . . . . . . . . . . . . . 314
6.7. Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 316
List of Authors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 321
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323
Foreword

“An image is a pure creation of spirit.” (Pierre Reverdy)
Today, in a world of eternal representation, we are the observers of the theater of
the grand image for as far as the eye can see, a theater which incessantly unfolds in the
marvelous recording box that is our brain. Though we see them, the touch and even
the substance of illustrations sometimes escape us completely, so much so that we
can almost not differentiate between representative illusion and the physical reality of
beings and things. Yet, the representation of the world in our eyes is not the same as
the one that we want to transpose, to put into images. There, the reality of that which
is visible is captured by our brains, which makes copies which are sometimes
faithful, sometimes untrue. To produce these images we have, since the dawn of
mankind, resorted to sometimes extremely complex alchemies, where invention has
struggled with various materials, as a result of which we have been able to leave
behind our illustrated drawings, the prints of our lives and of our societies.
For some 32,000 years man has not stopped etching, doodling, drawing, copying,
painting, reproducing – for nothing, for eternity – producing millions of infinite
writings and images which are the imperishable memory of his genius. How did he
do it, with which materials, on what, and why? The alchemy of representation, in its
great complexity, deserves to be slowed down, so that we can try to understand, for
example, how today’s images reach us in a kind of gigantic whirlwind, whereas 200
years ago these things were still rather sober. Or how else could we go from an
image that we can look at, to an image that is difficult to see, or to one that we
cannot even see with the naked eye? Whereas now we throw things away, in the past
images were preciously preserved. Are the images which we try to preserve today not
the same as the ones we were preserving yesterday?

Foreword written by Jörge DE SOUSA NORONHA.
xii Nano-Lithography
It is amongst the cavemen that that which I call the image maker can first be
outlined. Collating their visions, their dreams, their beliefs on cave walls, these first
imagicians undoubtedly bequeathed to us the only widely known account of this
period. In their wake, we will be able to better evaluate the formal evolution of the
visual representation of nature and things, this inevitable invention in which we
endeavor to capture the spirit through an artefact.
Man had to train long and hard to finally tame and durably transmit the images of
the world which surrounded him. The techniques employed across the ages to make
and convey these images, the materials, the pigments, the bindings, the instruments
and the mediums, either natural, chemical or manufactured, not only conditioned the
appearance of the image itself but also its durability.
Cave paintings, coins, palaces, churches, are just some of the mediums which have
left us with invaluable visual evidence of more or less remote pasts, sometimes
essential for putting together the history of humanity. If we consider the
manufacturing and the trading of images from the beginning, and in its totality, we
can distinguish two major periods: the longest, the pre-photographic; and the post-
photographic, which began in the first half of the 19th Century, and which is
therefore extremely recent. Admittedly, our eyes can see but they cannot take
photographs. The images that they collect are transitory fragments in a “band-
width”, a time kept in the memory, often lost, far from any material existence, and
for which any attempt at verbal transcription is on this side of reality. For other
animals, sight is part of a sub-conscious effort to survive. For man, by contrast, sight
is a conscious irreplaceable instrument, appreciating the outside world, which is an
integral part of his own physical and mental development. For us, to see is natural.
However, representing what we see calls upon a certain kind of initiation. How were
the first painters of history introduced to engraving and drawing? How were they
able to find or invent the tools and materials needed to succeed?
The tools, materials and shapes are the three essential ingredients needed to build
and formalize the representation of the visible. Footprints on sand, for example,
undoubtedly the first prints left by man, were already kinds of natural images of the
body, and most probably were the root of the original idea to make images. The tool
here was man’s own foot, with its shape, using a soft and flexible material, a support
able to keep an image. Thus, without any doubt, the earth and sand were among the
first image mediums, even before other sketches came to cover other materials, and
other surfaces.
The various attempts leading to the reproduction and spreading of visible images
or texts, little by little, drove man to develop very clever techniques, sometimes born
out of chance, or sometimes by increasingly elaborate research. The first stone
engravings (from before 600 BC) precede, by a long time, the first examples of