Motoshi Sasaki

Oxidative Curing of Hydrogen Silsesquioxane Resin Films by Electron Beam Irradiation without Additional Heatings and Characterization of the Cured Films

We have developed a new curing process for hydrogen silsesquioxane (HSQ) films, which is applicable for interlayer dielectrics of LSI devices. In this process, an electron beam was used as a curing source. As a result, a practical curing speed was obtained without additional heat treatments at ambient pressure, since electron beams accelerate the oxidative curing reaction on HSQ. The cured films exhibited properties for practical use such as thermal stability, which are equivalent to films cured conventionally by heat treatment. The cracking resistance of the electron-beam-cured films is excellent. A film of 3.0 µm thickness did not show any cracks, whereas a thermally cured film with a thickness of 1.25 µm showed cracks. Furthermore, electron-beam-cured films with a thickness of 2.5 µm did not show any cracks even after nitrogen annealing at 400°C for 1 h. The mechanism of oxidative curing of HSQ by electron beam irradiation was also studied.