High contrast photoresist developer

Abstract From the Canadian patent

A positive photoresist metal ion aqueous developer is provided that gives a high contrast to the photoresist. The developer disclosed comprises a formulation of aqueous alkali-base such as potassium hydroxide and a carboxylated surfactant. The incorporation of the carboxylated surfactant provides the unexpected increase in the contrast of the photoresist. The addition of the carboxylated surfactant increases the gamma from a typical photoresist gamma (.gamma.) of 3 or less to a gamma greater than 5. The high contrast photoresist provides linewidth control and affords improved process latitude in photoresist imaging. The linewidth control is particularly critical in cases where fine lines …