Neutral oxygen beam stripping of photo resist on porous ultra low-k materials

Integration of porous low-k materials for interconnect technology present many challenges to the etch, ash and cleaning processes. One challenge is the post etch removal of photo resist on open porous low-k films. Porous low-k films are very susceptible to damage by plasma processing, which can raise the overall k_eff of the film. Traditionally, a pure oxygen plasma ash is one method used for photo resist removal on CVD dielectrics. This method cannot be applied to exposed low-k films, because chemical and physical damage occurs. Successful photo resist removal on low-k films can be achieved by reducing chemistries or dilute O₂ processes in RIE etch tools. This work shows how an energetic neutral oxygen beam can be used to strip photo resist, without damaging the exposed low-k material.