Residual casting solvent

Two qualitative conclusions may be drawn from these fluorescence results. The first point is related to whether there is residual casting solvent that might affect the morphology of the film. It is not possible to comment on the presence of residual chlorobenzene or toluene from the results of this study because of the lack of any dramatic change in R or excimer band position upon annealing. No separate gravimetric studies of solvent evaporation were conducted in this work, although such experiments have been... 

The Probabilistic Approach allows for the explanation many previously unexplained dissolution phenomena the effect of added salts (7), the MW dependence (5) and the effect of residual casting solvent (35,3d) on the dissolution rate. 

Methanol-treated PIM-1, that was soaked in methanol for at least a day, to flush out any residual casting solvent and allow relaxation of chains in the swollen state, then dried under vacuum to constant weight. 

The goal of the present stu is to establish experimentally whether the differences in contaminant uptake such as those seen in our previous study (4) can be similarly attributed to variations in levels of residual casting solvent. Since the final shape of a lithographic relief image is determined by a large set of interdependent variables, it is difficult to characterize the effect of residual solvent on susceptibility to airborne contamination in an unambiguous way by SEM examination of resist patterns. In our prior work on NMP uptake (4), films... 

Recall that all films in this study and in our previous work were subjected to identical processing conditions. That, in combination with the evidence presented here on the role of residual casting solvent, leads to the condusion that polymer structural characteristics are the dominant factor controlling contaminant absorption. A closer mcamination of the data of Figure 5 support this conclusion ... 

Figure 5. Plot of amount of NMP absorbed in one hour by a series of thin polymer films versus their residual casting solvent contents.

We have presented evidence that residual casting solvent is relative unimportant in determining the propensity of a potymer film to absorb NMP. Films cast firom different solvents, but otherwise identical in composition and processing. 

An initial dissolution study was conducted with spin cast films containing different concentrations of PAC dispersed uniformly throughout the polymer matrix. Solutions containing S wt% solids in 2-etho ethanol were spun at 2000 rpm for 40 seconds yielding films that were approximately 1000 A. Thicknesses were determined by ellipsometry after the films were baked at 90 C for 30 minutes on an aluminum block in a convection oven to remove residual casting solvent. Samples with PAC concentrations varying from 0-50% by weight of polymer were prepared for study. 

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