Conductor fabrication process

The device fabrication process is illustrated in Figure 11.18a and can be described in the following steps. Step-I is the selection of two transparent substrates coated with a transparent conductor such as ITO, fluorine-doped tin oxide (FTO), or a high conductivity polymer, etc. In Step-II, one substrate... 

SEM micrograph of a via stack with six levels of conductors fabricated by EMM process [7]. 

In designing composites there often remain conflicting requirements that cannot easily be solved with a proper combination of phases. Materials for fuel cell electrodes are an example. They must simultaneously be porous for gases, catalyti-cally active, thermally inert, excellent electrical conductors, and have a large interface area with the electrolyte phase. To obtain an acceptable compromise for these properties, percolation of electronic and ionic conductors, open porosity, and interface wetting are imposed on the composite by choosing suitable components and fabrication processes. 

Permanent Plating Resist. The use of a permanent plating resist creates a flush surface, where the copper and resist are at the same height from the base laminate. This offers two distinct benefits. In the board fabrication process, after the conductors are formed, the... 

Interconnect. Three-dimensional structures require interconnections between the various levels. This is achieved by small, high aspect-ratio holes that provide electrical contact. These holes include the contact fills which connect the semiconductor silicon area of the device to the first-level metal, and the via holes which connect the first level metal to the second and subsequent metal levels (see Fig. 13.1). The interconnect presents a major fabrication challenge since these high-aspect holes, which may be as small as 0.25 im across, must be completely filled with a diffusion barrier material (such as CVD titanium nitride) and a conductor metal such as CVD tungsten. The ability to fill the interconnects is a major factor in selecting a thin-film deposition process. 

CVD is a maj or process in the production of thin films of all three categories of electronic materials semiconductors, conductors, and insulators. In this chapter, the role of CVD in the fabrication of semiconductors is reviewed. The CVD production of insulators, conductors, and diffusion barriers is reviewed in the following chapter. The major semiconductor materials in production or development are silicon, germanium, ni-V and II-VI compounds, silicon carbide, and diamond. 

---