Conductors, thick-film aluminum

This thick-film multichip module substrate (Figure 1.22) packaged the row and column driver circuits for an electroluminescent avionics flat panel cockpit display. The three-conductor-layer substrate is 86.4 x 111.8 mm (3.4 X 4.4 in.) in size with 43 metallized through vias in the alumina substrate for interconnections on both sides of the substrate. On the component side, the 14 row and column driver ICs are aluminum-wire-bonded with a total... 

K. Allison et al., Thick Film Conductor Compositions for Use with an Aluminum Nitride Substrate, U.S. patent no. 5,089,172, February 18,1992. 

Aluminum has a low density it is a strong metal and an excellent electrical conductor. Although it is strongly reducing and therefore easily oxidized, aluminum is resistant to corrosion because its surface is passivated in air by a stable oxide film. The thickness of the oxide layer can be increased by making aluminum the anode of an electrolytic cell the result is called anodized aluminum. Dyes may be added to the dilute sulfuric acid electrolyte used in the anodizing process to produce surface layers with different colors. 

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