Penetration depth of ion

The relative rate of molecular weight degradation is shown in Figure 12. The effects of the plasma are particularly intense within the top few thousand Angstroms of the film. The rapid decrease in degradation with depth can be explained by either the shallow penetration depth of ions or electrons that bombard the resist surface or by the rapid consumption of reactive species (e.g. halogen radicals) which diffuse into the polymer matrix. 

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