Colorless Transparent Polyimides with Balanced Dielectric and Optical Properties

Polyimides (PIs) have successfully entered the semiconductor and integrated circuit fields due to their excellent electrical insulation, compatibility with semiconductor processes, chemical resistance, and highly patternable nature. This chapter discusses the design and synthesis of high-transparency, low-dielectric PIs, emphasizing the balance between dielectric and optical properties. Key findings include the importance of structural design in achieving desirable properties and the role of process parameters in optimizing performance. Specifically, the incorporation of fluorinated groups (such as trifluoromethyl, partially fluorinated, and fully fluorinated structures), alicyclic structures, bulky pendant groups (such as triphenyl, triphenylmethyl, and naphthyl), non-coplanarstructures (such as spiro and cardo), and silicon-based particles have been widely applied in the development of high-transparency, low-dielectric PIs. The introduction of fluorinated monomers, while effective in reducing dielectric constants, often comes with high costs.