Formulation of resists

Formulation of Resist Solutions. Forty grams of a Novolak resin was mixed with 10 g of the photoactive compound, and dissolved in 100 g of bis-2-methoxy-ethylether. After wafers were spin-coated, the samples were immediately placed on a hot plate at 82 C for 14 min. The formulation procedure of a composite resist of poly (2-methyl-1-pentene sulfone) in the Novolak resin is as follows the polysulfone was mixed with the resin (13 wt% solid), and then dissolved in 2-methoxyethyl acetate the films were spin-coated onto silicon wafers, and then baked at 100°C for 20 min prior to electron beam exposure. 

There are many photoresists available commercially. These can be categorised into positive and negative tone resists. Various formulations of resists have differing properties (viscosity, ultimate achievable resolution, substrate adhesion etc.). Several classes of resist have thus been developed for different electronic applications. For example, high-resolution photolithography for patterning of submicron transistors requires a different resist to that needed for deep silicon etching of micro-electro-mechanical-systems (MEMS) stmctures. 

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