As Amorphous silicon devices spread into more products, the advantages inherant in continuous processing utilizing a plastic roll substrate will assume greater importance. Advantages include cost, ease of handling, shipping weight, steady state processing conditions and feedback control available in continuous processing. A new set of problems and constraints also comes with plastic substrates. These problems include mechanical strength with flexing, substrate surface defects, differential expalsion coefficients, shrinkage, and contaminant control. These problems along with efforts to evaluate and overcome them are discussed.