CVD Polymers

The method of CVD (chemical vapor deposition) is a versatile technique to fabricate high-quality thin films and structured surfaces in the nanometer regime from the vapor phase. Already widely used for the deposition of inorganic materials in the semiconductor industry, CVD has become the method of choice in many applications to process polymers as well. This highly scalable technique allows for synthesizing high-purity, defect-free films and for systematically tuning their chemical, mechanical and physical properties. In addition, vapor phase processing is critical for the deposition of insoluble materials including fluoropolymers, electrically conductive polymers, and highly crosslinked organic networks. Furthermore, CVD enables the coating of substrates which would otherwise dissolve or swell upon exposure to solvents.

The scope of the book encompasses CVD polymerization processes which directly translate the chemical mechanisms of traditional polymer synthesis and organic synthesis in homogeneous liquids into heterogeneous processes for the modification of solid surfaces. The book is structured into four parts, complemented by an introductory overview of the diverse process strategies for CVD of polymeric materials. The first part on the fundamentals of CVD polymers is followed by a detailed coverage of the materials chemistry of CVD polymers, including the main synthesis mechanisms and the resultant classes of materials. The third part focuses on the applications of these materials such as membrane modification and device fabrication. The final part discusses the potential for scale-up and commercialization of CVD polymers.

Autorentext

Karen K. Gleason is Associate Provost and the Alexander and I. Michael Kasser Professor of Chemical Engineering at MIT, USA. Her BSc and MSc degrees are from MIT and her PhD is from the University of California at Berkeley. Karen K. Gleason has authored more than 300 publications and holds 18 issued US patents for CVD polymers and their applications in optoelectronics, sensing, microfluidics, energy storage, and biomedical devices, and also for the surface modification of membranes. At MIT, she has served as Executive Officer of the Chemical Engineering Department; Associate Director for the Institute of Soldier Nanotechnologies; and as Associate Dean of Engineering for Research. She is a Member of the National Academy of Engineering, a Fellow of the American Institute of Chemical Engineering (AIChE) and has held the Donders Visiting Chair Professorship at Utrecht University in 2006. Her awards include the ID TechEx Printed Electronics Europe Best Technical Development Materials Award, the AIChE Process Development Research Award, and Young Investigator Awards from both the National Science Foundation and the Office of Naval Research.

Inhalt

List of Contributors XV

1 Overview of Chemically Vapor Deposited (CVD) Polymers 1
Karen K. Gleason

1.1 Motivation and Characteristics 1

1.1.1 Quality 2

1.1.2 Conformality 2

1.1.3 Durability 3

1.1.4 Composition 3

1.2 Fundamentals and Mechanisms 4

1.2.1 Gas Phase and Surface Reactions 4

1.2.2 The Monomer Saturation Ratio 5

1.2.3 Process Simplification and Substrate Independence 6

1.3 Scale-Up and Commercialization 6

1.4 Process and Materials Chemistry 7

1.4.1 Initiated CVD (iCVD) and Its Variants 8

1.4.2 Plasma Enhanced CVD (PECVD) 8

1.4.3 Poly(p-xylylene) (PPX) and Its Derivatives (Parylenes) 9

1.4.4 Oxidative CVD (oCVD) 9

1.4.5 Vapor Deposition Polymerization (VDP) and Molecular Layer Deposition (MLD) 9

1.4.6 Additional Methods 10

1.5 Summary 10

Acknowledgments 11

References 11

Part I: Fundamentals 13

2 Growth Mechanism, Kinetics, and Molecular Weight 15
Kenneth K. S. Lau

2.1 Introduction 15

2.2 iCVD Process 16

2.3 Kinetics and Growth Mechanism 18

2.3.1 Fluorocarbon Polymers 18

2.3.2 Organosilicon Polymers 25

2.3.3 Acrylate and Methacrylate Polymers 28

2.3.4 Styrene and Other Vinyl Polymers 37

2.3.5 Ring Opening Polymers 37

2.4 Summary 39

References 39

3 Copolymerization and Crosslinking 45
Yu Mao

3.1 Introduction 45

3.2 Copolymer Composition and Structure 46

3.2.1 Confirmation of iCVD Copolymerization 46

3.2.2 Analysis of Copolymer Composition 47

3.2.3 Compositional Gradient 50

3.3 Copolymerization Kinetics 52

3.3.1 Copolymerization Equation and Reactivity Ratio 52

3.3.2 Types of iCVD Copolymerization 55

3.4 Tunable Properties of iCVD Copolymers 56

3.4.1 Mechanical Properties 56

3.4.2 Swelling 58

3.4.3 Thermal Properties 60

3.4.4 Surface Properties 61

3.5 Conclusions 62

References 62

4 Non-Thermal Initiation Strategies and Grafting 65
Daniel D. Burkey

4.1 Introduction 65

4.2 Initiation Strategies 65

4.2.1 Plasma Initiation Strategies 65

4.2.2 Photoinitiation Strategies 71

4.3 Grafting 76

4.3.1 Surface Modification of Organic Substrates 77

4.3.2 Surface Modification of Inorganic Substrates 78

4.3.3 Grafting Summary 82

4.4 Summary 82

References 84

5 Conformal Polymer CVD 87
Salmaan Baxamusa

5.1 Introduction 87

5.2 Vapor Phase Transport 87

5.3 Conformal Polymer Coating Applications 88

5.4 Conformal Polymer Coating Technologies 89

5.5 Gas and Surface Reactions 90

5.6 The Reaction-Diffusion Model 93

5.6.1 Reaction and Diffusion in a Pore 93

5.6.2 Initiator Controlled Consumption 96

5.6.3 Factors Affecting the Initiator Sticking Probability 99

5.6.4 Monomer Controlled Consumption 100

5.6.5 Other Polymer CVD Systems 101

5.7 Applications 102

5.8 Conclusion 106

Acknowledgment 107

References 107

6 Plasma Enhanced-Chemical Vapor Deposited Polymers: Plasma Phase Reactions, PlasmaSurface Interactions, and Film Properties 111
Mariadriana Creatore and Alberto Perrotta

6.1 Introduction: Chemical Vapor Deposition Methods, Advantages, and Challenges 111

6.2 Plasma Parameters, Plasma Phase Reactions, and the Role of Diagnostics 114

6.3 Plasma Polymerization: Is It Just Chemistry? The Role of Ions in Film Growth 117 6.4 Considerations on the Macroscopic Kinetics Approach to Plasma Polymerization...