2. Semiconductor Technology Overview

Modern VLSI technology uses very complex equipment and sophisticated materials. Starting from the raw semiconductor wafer, integrated circuits require several hundred individual process steps before becoming ready for packaging and electrical testing. In this chapter the most important process steps are briefly described.

The process steps can roughly be classified in two groups:

• Structural processing (etching, deposition, oxidation, etc),
• Thermal processing and doping (ion implantation, annealing, etc).
  

The first group comprehends the processes that force a change in the material's structure, while the second only a modification in their properties (like the doping profile). As most of the process steps are not performed over the entire wafer, a method to selectively apply them to a certain region of the wafer is necessary. This is done by lithography, not included in either groups, as it is necessary in general. We will describe it in the first place.