chapter 15-Principles of Plasma Discharges and Materials Processing Second Edition精品.pdfVIP

CHAPTER 15 ETCHING 15.1 ETCH REQUIREMENTS AND PROCESSES Plasma etching is a key process for removing material from surfaces. The process can be chemically selective, removing one type of material while leaving other materials unaffected, and can be anisotropic, removing material at the bottom of a trench while leaving the same material on the sidewalls unaffected. Plasma etching is the only commercially viable technology for anisotropic removal of material from surfaces. As such, it is an indispensable part of modern integrated circuit fabrication technology, as was described in Chapter 1. For a more complete description of this area, the reader should consult other sources; for example, Manos and Flamm (1989, Chapters 1 and 2). Although there are many other areas of application, nearly all modern develop- ments in plasma etching have been driven by their potential for integrated circuit fabrication. In this chapter, we focus almost exclusively on this area, placing empha- sis on the key concepts that determine etch rate, selectivity, and anisotropy in plasma etch processes. In this section, we introduce typical etch requirements and possible tradeoffs among them and describe the four types of plasma etch processes. In Section 15.2, some simple models of surface etching and discharge kinetics are described and a general chemical framework for plasma etching is introduced. In Section 15.3, the use of halogens to etch silicon is discussed. In particular, fluorine atom etching of silicon has been the most well-studied etch system, providing insight into other less well characterized systems. In Section 15.4, some descriptions of silicon oxide and nitride etching, metal etching, and photoresist etching are given. Principles of Plasma Discharges and Materials Processing, by M. A. Lieberman and A. J. Lichtenberg. ISBN 0-471-72001-1 Copyri