Chemical trimming overcoat: an advanced composition and process for photoresist enhancement in lithography

In the semiconductor manufacturing industry, photoresist materials are used for transferring an image to one or more underlying layers. To increase the integration density of semiconductor devices and reduce cost of ownership, continuous development efforts towards advanced lithography processes, such as multiple patterning methods, have been devoted to reduce critical dimension. Multiple patterning processes, however, often encounter challenges to obtain an appreciable process window due to the poor aerial image contrast at the defocus region, not to mention the complexity in process and high cost. Herein, we report a novel CTOTM photoresist trimming solution as a post-lithography spin-on method to enhance photoresist performance in not only effectively reducing critical dimension, but also enabling larger process window, lower line width roughness, less scum and lower defectivity. This is a versatile process that is compatible with both acrylic and polyhydroxystyrene types of photoresists, therefore allowing it to become a general process for a wide range of applications across ArF, KrF and EUV lithography.