New dielectric tape materials for LTCC: characterisation and modelling of microwave properties [Elektronische Ressource] / vorgelegt von Ashkan Naeini Ali Akbari

Ashkan.Naeini

Informations

• Publié par: rheinisch-westfalischen_technischen_hochschule_-rwth-_aachen
• Publié le: 01 janvier 2004
• Nombre de lectures: 44
• Langue: Deutsch
• Poids de l'ouvrage: 23 Mo

Extrait

“New Dielectric Tape Materials for LTCC:
Characterisation and Modelling of
Microwave Properties”



Von der Fakultät für
Elektrotechnik und Informationstechnik der
Rheinisch-Westfälischen Technischen Hochschule Aachen
zur Erlangung des akademischen Grades eines Doktors der
Ingenieurwissenschaften genehmigte Dissertation


vorgelegt von


Diplom-Ingenieur
Ashkan Naeini Ali Akbari

aus Abadan, Iran


Berichter: Universitätsprofessor Dr.-Ing. Rainer M. Waser
Universitätsprofessor Dr.-Ing. Rolf H. Jansen


Tag der mündlichen Prüfung: 11. Mai 2004


Diese Dissertation ist auf den Internetseiten der Hochschulbibliothek online verfügbar





i

Table of Contents



Acknowledgements
1Introduction 1
1.1. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2. State of knowledge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3. Tasks of thesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Background 5
2.1. Dielectric Properties of Solid-States
2.1.1 Polarisability . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.1.2 Local Electric Field . . . . . . . . . . . . . . . . . . . . . . . . 10
2.1.3 Clausius-Mossotti Relation . . . . . . . . . . . . . . . . . . . . 13
2.1.4 Dielectric Constants . . . . . . . . . . . . . . . . . . . . . . . . 14
2.1.5 Dielectric Loss . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.1.6 Temperature Coefficient of Permittivity . . . . . . . . . . . . 16
2.1.7 Quantum Mechanical Aspect of Dielectric Properties . . . . , . . 17
2.2 Homogenisation of Mixtures
2.2.1 Effective Relative Permittivity ε . . . . . . . . . . . . . . . . 19 eff
2.2.2 Wiener Boundaries . . . . . . . . . . . . . . . . . . . . . . . . 20
2.2.3 Maxwell-Garnett Mixing Rule . . . . . . . . . . . . . . . . 21
2.2.4 Symmetric Bruggeman Effective Medium Theory . . . . . . . . 26
2.2.5 Validity and Percolation . . . . . . . . . . . . . . . . . . . . 28
2.2.6 Landau-Lifshitz-Looyenga Mixture Formula . . . . . . . . . 29
2.2.7 Lichtenecker Empirical Mixture Formula . . . . . . . . . . . . . 32
2.3 HF Characterisation of microwave ceramics
2.3.1 Q-Factor vs. Tanδ . . . . . . . . . . . . . . . . . . . . . . . . 36
2.3.2 Dielectric Resonators . . . . . . . . . . . . . . . . . . . . . . . . 39
2.3.3 Temperature Coefficient of Resonant Frequency (TCf) . . . . . 43
2.3.4 Split- Post dielectric resonator method. (SPDR) . . . . . . . . 45 ii
2.3.5 Test structures . . . . . . . . . . . . . . . . . . . . . . . . . 47
2.4 Microwave Ceramics
2.4.1 History . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
2.4.2 BaO-Re O -TiO , Re=(La-Gd) ternary System . . . . . . . . 53 2 3 2
2.4.3 Low Temperature Co-fired Ceramics . . . . . . . . . . . . 56
3 Development of high-K LTCC Materials 58
3.1 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
3.2 Passive and Reactive Densification . . . . . . . . . . . . . . . . . . . . 60
3.3 Experimental Procedure . . . . . . . . . . . . . . . . . . . . . . . . . 61
3.3.1 Specimen Preparation . . . . . . . . . . . . . . . . . . . . . 61
3.3.2 Microstructure Analysis . . . . . . . . . . . . . . . . . . . . . 63
3.3.3 Dielectric Properties Measurement . . . . . . . . . . . . . . . . . 67
3.4 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
3.4.1 Analytical Characterization
3.4.1.1 Passive Glass-rich Approaches with LBT Glass . . . . . . . 72
3.4.1.2 Reactive Ceramic-rich Approaches with BBSZ Glass . . . . 76
3.4.1.3 Metallic Interface . . . . . . . . . . . . . . . . . . . . . 92
3.4.2 Dielectric Characterization of Tapes and Substrates . . . . . . . . . 93
3.4.2.1 Split-Post Dielectric Resonator - SPDR . . . . . . . . 93
3.4.2.2 Test Structures . . . . . . . . . . . . . . . . 103
4 Simulations and Discussions 112
4.1 Densification Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
4.2 Dielectric Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
4.3 Microstructural Modelling and Simulation . . . . . . . . . . . . . . . . 117
4.3.1 Electrostatics Approach . . . . . . . . . . . . . . . . . . . . . . 119
4.3.2 Quasi-Static Approximation . . . . . . . . . . . . . . . . . . . . 121
4.3.3 Plane-Wave Propagation Approach . . . . . . . . . . . . . . . . . 123
4.3.4 Verification of Classical Mixture Formulae . . . . . . . . . . . . . 125
4.3.5 Ceramic Rich Glass-Ceramic Model . . . . . . . . . . . . . . . . . 128
4.3.6 Outlines to the Quantum Mechanical aspect of material simulation . 131
5 Conclusions 137
6 References 139 iii

iv

Acknowledgements

First of all, I would like to express my gratitude to Prof. Dr. Reiner Waser, who promotes me for a
Ph.D degree and supports me very kindly with his advice during my dissertation. I am also very
thankful to my local tutor Dr. Oliver Dernovsek for his invaluable support and patience during the past
three years of collaboration.
I am also in debt to Mr. Wolfram Wersing for many valuable discussions and suggestions and for his
final correction work on this dissertation. I thank him for his guidance through my time at Siemens
AG.
Not to mention Dr. Karl Kemper and Dr. Alfred Felder from the MM2 Ceramic Department of
Siemens AG, who offered me this opportunity and gave me the chance to complete my dissertation
work, respectively.
I am also greatly obliged to Dr. Steffen Walter for his crucial contributions to the microstructural
analysis and to Ms. Ruth Maenner for her unconfined endeavours by processing and manufacturing of
LTCC test layouts.
Finally, I would like to express my best thanks to my family, Fariba my wife and Lara my daughter,
who have never complained about my endless overtime and failures. v

1 Introduction 1


1 Introduction

1.1 Motivation

Recently, the field of consumer electronics has made tremendous progress; electronic devices have
become an essential part of our daily lives. Extremely compact portable devices, such as mobile
phones or pocket computers, are carried by almost everyone everywhere. Certainly, this unstoppable
success is caused by continuous improvements in module reliability and performance, with concurrent
size and weight reductions. During the last decade, the demands made of material and electrical
packaging of modules have increased greatly, leading to fruitful developments in material science of
electrical packaging. Today, many aspects of electrical packages are specified, such as long-term
protection in harsh environments, thermal conductivity, electromagnetic properties and compatibility,
etc. Current multi-functional packages with improved integration feasibility significantly enhance the
size, functionality and performance of electronic modules [1].
Particularly, in RF and HF applications both conductance and dielectric losses are crucial. Here,
ceramic packaging deserves special attention due to its excellent properties at microwave and
millimeter frequencies in microwave multi-chip module (MMCM) design [2]. Nevertheless, packages
must offer ever-better integration and functionality; this encourages the development of new ceramic
manufacturing processes for packaging.
Low temperature co-fired ceramic (LTCC) technology is among the most promising approaches to
miniaturization of electronics packaging. It exploits both the ceramic and metallic benefits and a
reliable screen-printing technology, with the unique ability to integrate a broad variety of components
(such as capacitors and inductors) into a very compact arrangement. It was recognized very early that
demands for higher integration could only be met by significantly improving the dielectric properties
of LTCC. In fact, the latter perception prompted us to study the high-K LTCC. As the solution
required new composite approaches, microstructural modeling of the physical behavior and dielectric
response of the multiphase composite is indispensable for a fundamen