Preventing dielectric damage of low-k organic siloxane by passivation treatment

An organic SOG, the Hybird-Organic-Siloxane-Polymer (HOSP), has high applicability to ULSI processes, because of the low dielectric constant of about 2.5. However, the HOSP film will be damaged after photoresist removal. The function groups of HOSP will be destroyed by O₂ plasma ashing and chemical wet stripper, which leads to electrical degradation. In order to avoid the issue, H₂ plasma treatment is proposed to prevent HOSP film from photoresisit stripping damage. It is found that leakage current is decreased significantly and the dielectric constant is still maintained at a low k value even after photoresist stripping. Therefore, H₂ plasma treatment is an effective technique to enhance the resistance of HOSP film against photoresist stripping damage.