Real-time measurements of plasma photoresist modifications: The role of plasma vacuum ultraviolet radiation and ions

Plasma-induced roughness development of photoresist (PR) can be due to synergistic interactions of surface modifications introduced by ions, bulk material modifications by ultraviolet (UV)/vacuum ultraviolet (VUV) radiation, and increased temperature. While previous work identified the individual contributions of energetic ions and UV/VUV radiation, the dynamics of the concurrent modifications remained unclear. The authors studied the interactions of plasma radiation and ions with 193 nm PR and 248 nm PR in Ar plasma by in situ ellipsometry. Ellipsometry provides valuable information on changes in film thickness and material optical properties in real-time during plasma processing. MgF2, sapphire, and glass optical filters were used to reduce the plasma-material interactions to the radiation component of a selected wavelength range in the UV/VUV spectral region. Ar plasma radiation and its transmission through different optical filters were characterized by VUV spectroscopy. This characterization allowed ...

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