ABSTRACT
The main application of polyimides is the insulation or the passivation layers of electronic devices, where the pattern formation with the thick film layer is required. The high thermogravimetry (Tg) and the small free volume of polyimides inhibit the mobility of reacting species induced by photochemical reactions. This chapter discusses some basic factors that determine the sensitivity of polymeric materials and the amplification mechanisms used for photopolymers. It describes some examples of photosensitive polyimides synthesized based on the chemical amplification mechanism. Recently, an acid-catalyzed reaction has been attracting the interest of researchers in the field of microlithography, since it provides photoresists with high sensitivity, as well as high resolution for deep UV exposure. Photoacid generators (PAGs) are an important element in the acidolysis mechanism as they govern the spectral sensitivity and the sensitivity values of photosensitive polymers. Photosensitive polyimides may require sensitivity to near-UV light, since g- and i-line steppers are the most common exposing system in electronic device manufacture.
