Photoacid generator formation

Figure 5 shows the effect of incorporation of hydrophilic units such as amide or ether units into the photoacid generating polymers on the polysiloxane formation rate at the irradiated film surface. NIS unit fractions of 1, 2b, 3 and 6 were 0.17, 0.24,... 

Plate 2. Image formation (upon photoacid generation) within photosensitive polymer films for assembly of multi-layered structures. Two-photon fluorescence LSCM imaging usingfs pulsed near-IR pump allows for 3-D volumetric imaging of the layered structure. 

One approach to provide resists with high sensitivity and contrast involves the principle of chemical amplification (CA) (6-8), The amplification effect is achieved by employing a photo generated acid as a catalyst to carry out a cascade of chemical reactions in the resist film. Catalytic chain lengths of >1000 have been reported in the literature (9,10), However, the high catalytic chain lengths also enhance the resist s sensitivity to airborne basic contaminants and basic moieties on the substrate (11,12), In a positive tone resist such deactivation of the photoacid by airborne or substrate bound basic contaminants results in T-tops or foot formation respectively. 

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