The novel pattern method of low-k hybrid-organic-siloxane-polymer film using X-ray exposure

An organic low dielectric constant (low-k) material, hybrid-organic-siloxane-polymer (HOSP), is integrated into multilevel interconnection using X-ray exposure technology. In conventional IC integration processes, photoresist (PR) stripping with O₂ plasma and wet chemical stripper is an inevitable step. However, dielectric degradation often occurs when low-k dielectrics undergo the PR stripping process. This limits the application of incorporating low-k material into semiconductor fabrication. In order to overcome the integration issue, a novel pattern method, X-ray direct patterning is proposed. In this technology, the dielectric regions illuminated by X-ray will be cross-linked, forming the desired patterns. At the same time, the regions without X-ray illumination are dissolvable in a solvent of HOSP film. Direct-patterning processes have several advantages: (1) they do not need PR to define patterns; thereby the damage from PR stripping can be eliminated, (2) the complex etching on low-k dielectrics can be eliminated, (3) the process steps are simplified. In this work, we will investigate the dielectric properties of HOSP film with X-ray curing for the first time. Additionally, a scanning electron microscope image of circle pattern was made to verify the process practicability.