Chemical Vapor Deposition of Tungsten and Tungsten Silicides for VLSI/ ULSI Applications


  • John E.J. Schmitz, Philips Semiconductor; former COO of SEMATECH

This monograph condenses the relevant and pertinent literature on blanket and selective CVD of tungsten (W) into a single manageable volume. The book supplies the reader with the necessary background to bring up, fine tune, and successfully maintain a CVD-W process in a production set-up. Materials deposition chemistry, equipment, process technology, developments, and applications are described.
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Engineers and technologists in the semiconductor, optoelectronic, optics, cutting tool, refractory fibers, filter and other industries.


Book information

  • Published: December 1992
  • ISBN: 978-0-8155-1288-2


"After reading this book, an engineer should have all the necessary background." - European Semiconductor

Table of Contents

1. Introduction 1.1 Scaling down 1.2 Electrical contacts 1.3 Device reliability 1.4 Contact planarization and design rules2. The Blanket Tungsten Approach 2.1 Principal steps 2.2 Tungsten adhesion 2.3 Blanket deposition of tungsten 2.4 Etch back of blanket tungsten 2.5 Degree of planarization and the contact diameter 2.6 Blanket tungsten material characterization3. The Selective Tungsten Approach 3.1 Principal steps 3.2 Types of substrates 3.3 Types of dielectric layers 3.4 Chemistry of selective tungsten 3.5 Mechanisms of selectivity loss 3.6 Electrical characterization4. Blanket Versus Selective Tungsten 4.1 Feasibility of selective and blanket contact or via fill 4.2 Costs of the contact/via fill process 4.3 World wide status of CVD of tungsten 4.4 Conclusion5. Tungsten as Interconnect Material 5.1 Weaknesses of aluminum internconnects 5.2 Tungsten interconnects 5.3 Issues of tungsten interconnects6. The Chemistry of CVD-W and Properties of Tungsten 6.1 CVD tungsten source material 6.2 Experimental deposition rate relations obtained for the H2/WF6 chemistry 6.3 Some properties of tungsten 6.4 Contamination issues in CVD-W7. The Deposition Equipment 7.1 Hot wall reactors 7.2 Cold wall reactors 7.3 Industrial reactors 7.4 Future reactor developments8. Miscellaneous 8.1 Tungsten gates 8.2 Selective growth on implanted oxide 8.3 Buried tungsten 8.4 Alternative deposition techniques 8.5 Alternative plug processes9. Chemical Vapor Deposition of Tungsten Silicide 9.1 Introduction 9.2 WSix for polycide applications 9.3 Silicide deposition methods 9.4 CVD of WSix 9.5 CVD-WSix based on SiH4/WF6 chemistry 9.6 WSix based on SiH2Cl2/WF6 chemistry 9.7 Fluorine content in CVD-WSix films 9.8 Stress in CVD-WSix films 9.9 Step coverage of CVD-WSix films 9.10 ConclusionsReferencesAuthor IndexSubject IndexAppendix: Unit Cells of W and WSi2