Newly developed low-density methylsiloxane spin-on-glass films

Spin-on-glass (SOG) solution has been prepared from methyltriethoxysilane and dimethoxymethyl-3,3,3 -trifluoropropylsilane. Trifluoropropyl groups attached to silicon are thermally decomposed by curing at 450 degrees C in nitrogen. Since the overall methylsiloxane network is maintained without a significant shrinkage upon the thermal decomposition of trifluoropropyl groups, vacant spaces whose sizes are comparable to those of trifluoropropyl groups are introduced into the methylsiloxane network, leading to the low-density film with the Brunauer, Emmet and Teller (BET) surface area of 270 m(2)/g. The film shows the dielectric constant of 2.3, heat stability, low moisture uptake, good planarization property and no corrosion toward aluminum conducting lines.