High-Reliability Lithography Performed by Ultrasonic and Surfactant-Added Developing System

Formation of high-precision fine resist patterns has been achieved by an effective removal of dissolved resist polymers, that is, the reaction products of the development process. Also, it has been found that the reaction products give rise to the degradation of the resist contrast, resist sensitivity, and process margins. In order to remove the reaction products, two techniques have been employed, namely physical method of development with agitation (ultrasonic waves or with a stirrer) and chemical method of adding surfactant to the developer. By combining physical and chemical methods, the dissolved polymers have been effectively removed, thus allowing the resist to reveal its inherent patterning pertormance.