Dissolution Behavior of Photoresists: An In-situ Analysis

The characterization of the photoresist dissolution process after exposure has been continuously investigated in search for possible clues in the development of optimal photoresist materials and processes suit the requirements for next generation lithography. In this paper, an in-situ analysis of the photoresist's dissolution behavior is performed utilizing high-speed atomic force microscopy. Here, the physical changes in the surface of the exposed extreme ultraviolet (EUV) photoresist film is observed in real-time before, during and after the development process. This new information on the actual pattern formation of photoresists provides clues on how to better understand its mechanism and in effect further improve its performance. In this work, a comparison of the dissolution characteristics in terms of EUV photoresist platform (acryl-based polymer and fullerene-based molecular resist) in tetramethylammonium hydroxide (TMAH) developer was performed. Moreover, using the same polymer resist, the dissolution characteristic difference between the TMAH and tetrabutylammonium hydroxide (TBAH) developers was analyzed.