Dual damascene patterning for full spin-on stack of porous low-K material

In this article the dual damascene (DD) patterning has been examined for a full spin-on stack of a low-K material in K-value of 2.2 generation, i.e. LKD-5109 with dual low-K spin-on hard masks (SoHM). Compared to conventional CVD-deposited dual hard masks (dHM), the top spin-on HM has a wider range of thickness for which standing waves in the resist can be prevented. Furthermore, an etch selectivity has been obtained of more than 30 for LKD-5109 towards organic SoHM using fluorocarbon chemistries. Through the design of dHM structure and etch process development, it was possible to reduce the number of steps using an in-situ resist ash and organic SoHM strip during etching. A DD 0.2 /spl mu/m trench/via structure was successfully etched.