Low Si-OH ORMOCER ®s for Dielectrical and Optical Interconnection Technology

ORMOCER ®* s (inorganic-organic hybrid polymers) with low Si-OH content were synthesized by a new sol-gel route. Optimization of the sol-gel process parameters (catalyst, temperature etc.) was performed in order to achieve reproducible low cost materials which are photo-patternable even in higher layer thicknesses up to 150 μm within one step without cracking or delamination. The materials combine low losses in the NIR region (0.2 dB/cm at 1310 nm and 0.5 dB/cm at 1550 nm without fluorination!) with low dielectric constants (3.3 at 10 kHz). Beside the dielectric and optical properties the materials have a variety of additional advantages for interconnection technology: good wetting and adhesion on various substrates (e.g. glass, silicon and several polymers), low processing temperatures (postbake below 160 °C), high thermal stability (up to 270 °C) and a tunable refractive index. Details of chemical synthesis and characterization as well as photo-lithographic processing of ORMOCER ® materials are presented.