Problems with silicon incorporation

There are several problems encountered with silicon containing polymers that affect their lithographic properties. First, a decrease in Tg often accompanies silicon incorporation into a polymer. This may lead to dimensional instability of features during processing. Also, the hydrophobic nature of most useful silicon substituents may hinder the aqueous development of these resists. Careful selection of the polymer components can alleviate and/or eliminate these problems. 

To mitigate the problem, a diffusion barrier is incorporated between the aluminum and the silicon (see Sec. 5 below). It is also possible to replace aluminum by alloys of aluminum and copper or aluminum and silicon, which have less tendency to electromigration. These alloys are usually deposited by bias sputtering. However, they offer only a temporary solution as electromigration will still occur as greater densities of circuit elements are introduced. It was recently determined that improvements in the deposition of aluminum by MOCVD at low temperature with a dimethyl aluminum hydride precursor may reduce the problem.bl... 

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