Pattern collapse [Elektronische Ressource] : the mechanical stability and solid bridging of semiconductor nanostructures / vorgelegt von Daniel Peter

Peterda

Sujets

• Naturwissenschaften

Informations

• Publié par: christian-albrechts-universitat_zu_kiel
• Publié le: 01 janvier 2010
• Nombre de lectures: 81
• Langue: Deutsch
• Poids de l'ouvrage: 23 Mo

Extrait

Pattern Collapse
The Mechanical Stability and Solid Bridging of
Semiconductor Nanostructures



Dissertation
zur Erlangung des Doktorgrades
der Mathematisch-Naturwissenschaftlichen Fakultät
der Christian-Albrechts-Universität zu Kiel



vorgelegt von
Daniel Peter
aus Laufenthal



Villach, 2010





















Referent: Prof. Dr. Bensch
Korreferent: Prof. Dr. Kienle
Tag der Prüfung: 12.11.2010
Zum Druck genehmigt: 12.11.2010
ii
Erklärung
Hiermit erkläre ich daß ich die vorliegende Arbeit selbstständig und nur mit den
angegebenen Hilfsmitteln angefertigt habe und erstmalig im Rahmen eines
Prüfungsverfahrens vorgelegt wird. Die Arbeit ist nach Inhalt und Form abgesehen
von der Beratung durch den Betreuer meine eigene Arbeit welche unter Einhaltung
der Regeln guter wissenschaftlicher Praxis der Deutschen Forschungsgemeinschaft
entstanden ist. Dies ist mein erster Promotionsversuch.

Villach den 09.09.2010

Daniel Peter




iii Contents
Contents
Erklärung .................................................................................................................... iii
Contents ..................................................................................................................... iv
Acknowledgements ................................................................................................... vii
Abstract ...................................................................................................................... ix
Zusammenfassung ...................................................................................................... x
List of Symbols ........................................................................................................... xi
Abbreviations .......................................................................................................... xi
Formula Symbols ................................................................................................... xii
I Introduction .......................................................................................................... 1
1.1 Background ................................................................................................... 1
1.2 Semiconductor history & Moore’s law ............................................................ 3
1.3 Semiconductor Devices ................................................................................. 7
1.4 Semiconductor Structures with High Aspect Ratios....................................... 9
1.4.1 DRAM Capacitors ................................................................................... 9
1.4.2 Shallow Trench Isolation Structures ...................................................... 11
1.4.3 MEMS Structures .................................................................................. 13
1.5 Wet Surface Processing of Silicon Wafers .................................................. 14
1.6 Pattern Collapse .......................................................................................... 16
1.6.1 Definition and Standard Surface Tension Model ................................... 16
1.6.2 Pattern Collapse for MEMS Devices ..................................................... 18
iv Contents
1.6.3 Concepts for Prevention of Pattern Collapse in Microelectronics .......... 19
1.6.4 Pattern Collapse Theories Other than Surface Tension ........................ 20
II Theory ............................................................................................................... 23
2.1 Forces at the Nanoscale during Drying ....................................................... 23
2.1.1 van der Waals Forces ........................................................................... 23
2.1.2 Hydrogen Bonding ................................................................................ 24
2.1.3 Solid Bridging ........................................................................................ 24
2.1.4 Electrostatic Forces .............................................................................. 24
2.1.5 Centrifugal Forces ................................................................................. 25
2.1.6 Capillary Force ...................................................................................... 26
2.1.7 Evaluation of the Forces ....................................................................... 28
2.2 Beam Sway Models ..................................................................................... 31
2.2.1 Analytical Model .................................................................................... 31
2.2.2 Stress Analysis ..................................................................................... 33
2.2.3 Pattern Collapse Analysis ..................................................................... 34
III Methods ............................................................................................................. 36
3.1 Materials ...................................................................................................... 36
3.1.1 Semiconductor Line Structures (ASAP 300) ......................................... 36
3.1.2 AFM Tips and Experimental Setup ....................................................... 38
3.1.3 Silicon Nanoparticles and Preparation Methods ................................... 39
3.1.4 Chemicals ............................................................................................. 40
3.2 Analytical Techniques .................................................................................. 42
3.2.1 Lateral Force Microscopy ...................................................................... 42
3.2.2 Transmission Electron Microscopy ....................................................... 48
3.2.3 X-ray Photoelectron Spectroscopy (XPS) ............................................. 50
3.2.4 Nuclear Magnetic Resonance Spectroscopy ........................................ 50
3.2.5 Electro Spray Ionization – Mass Spectrometry ..................................... 50
3.2.6 Analytical Equipment ............................................................................ 51
v Contents
IV Results and Discussion ..................................................................................... 52
4.1 Pattern Collapse by AFM ............................................................................. 53
4.2 Fracture Strength of Polysilicon in Nanostructures ...................................... 62
4.3 Influence of the Chemicals Used for Semiconductor Drying on the
Mechanical Stability of Nanostructures ................................................................. 72
4.4 Influence of the Bulk Liquid Media vs. the Solid-Liquid Interface ................. 82
4.5 Influence of Alcohols and the Solid-Liquid Interface .................................... 92
4.6 Solid Bridging Studied with Silicon Nanoparticles ....................................... 97
V Conclusions and Outlook ................................................................................. 104
List of Figures ......................................................................................................... 108
Bibliography ............................................................................................................ 111
Curriculum Vitae ..................................................................................................... 123

vi Acknowledgements
Acknowledgements
First of all I would like to thank the company SEZ AG for initiating this PhD thesis and
Lam Research Corporation for their continued and great support after the acquisition
of SEZ AG.
I wish to thank my PhD advisor, Prof. Dr. Wolfgang Bensch, for his interest in this
topic and his guidance especially for the experiments with the nanoparticles. For the
examination of and his interest in this thesis, I would like to thank the co-referent
Prof. Dr. Kienle. Additionally, I would like to thank him and Andriy Lotnyk for his great
support with TEM analyses.
I am very grateful for the support and advice of Prof. Dr. Alfred Lechner, who initiated
and promoted this thesis throughout its development. I would like to thank his team
for the help with the experiments at the University of Applied Sciences Regensburg.
I would like to express my appreciation and gratitude to my company advisor,
Dr. Michael Dalmer. Despite his full calendar, he always found some time to discuss
the latest results with me. I am especially grateful that he allowed me to concentrate
on my experiments. A big word of thanks goes to Hans Kruwinus for giving me the
chance to work on this topic. Our fruitful discussions always resulted in new ideas.
In this place, I would like to thank Prof. Dr. Robert Stark and Dr. Alexander Gigler for
the collaboration with the AFM measurements in liquid media. Especially, I would like
to say thank you for the good discussions and the smooth collaboration with the
whole group at the LMU Munich.
Furthermore, the support of the Institute for Electron Microscop