Page 85 - Microsensors, MEMS and Smart Devices - Gardner Varadhan and Awadelkarim

66 STANDARD MICROELECTRONIC TECHNOLOGIES

Rotation

' Polycrystalline silicon rod

O RF heating coil
Molten zone

Single-crystal silicon
product rod

Silicon seed crystal

Figure 4.4 Schematic diagram of the apparatus used in a float-zone process to grow single-crystal
silicon

4.2.2 Wafer Manufacture

The conventional base, or substrate, within which microelectronic devices and ICs are
fabricated, is the silicon wafer. Other substrates (e.g. glass, dielectric) upon which hybrid
circuits are built are covered later in this chapter. There are a number of production
steps that are required to turn a single-crystal silicon boule produced by Czochralski
or float-zone crystal growth into a silicon wafer suitable for monolithic processing,
namely,

1. Diameter sizing

2. Orientation
3. Slicing
4. Etching
5. Polishing
6. Cleaning