As the dimension of IC devices continues to shrink, interconnection delay becomes a limiting factor to increase device speed. Therefore, it is necessary to use low-dielectric-constant (low-k) materials to reduce the capacitance between the metal interconnection. In this work, two kinds of low-k silisesquioxane have been investigated: Methylsilsesquioxane (MSQ) and Hydrogen silisesquioxane (HSQ). The adhesion between silicon nitride (Si3N4) and low-k MSQ or HSQ has been examined. The adhesion strength can be improved by various plasma treatments on top of the silisesquioxane. The adhesion strength between MSQ and Si3N4 can be increased by NH3 or H-2 plasma treatment. On the other hand, the adhesion strength between HSQ and Si3N4 is only increased by NH3 treatment effectively. Surface properties and electrical characterization of low-k silisesquioxane have also been examined after various plasma treatments. (C) 2004 Published by Elsevier B.V.