Effect of UV, IR and microwave radiation on Tween-80 porogen based low-k films

Abstract

Low dielectric constant (low-k) films due to their potential application as an inter-layer dielectric (ILD) attracted significant attention of researchers and scientists. Porous low-k films like xerogel, aerogel, porogen based and hybrid films are extensively investigated as they have dielectric constant value less than that of SiO2. Considering the advantages of porous low-k films, current investigation focused onto the study of porogen based porous low-k films. To obtain low-k films, solgel based spin-on technique is used. Incorporation of Tween-80 porogen in deposited low-k films is confirmed through the presence of –CH2-CH3 group around 2856–2916 cm−1 in FTIR spectra. Removal of porogen material from film matrix was done by using radiation exposure of samples and is confirmed through FTIR analysis. Refractive indices (RI) of deposited porogen based films treated with UV, IR and microwave radiations are observed to be 1.28, 1.29 and 1.33, respectively. Further, density of IR, UV and microwave radiation is calculated from RI, and is observed to be decreased for UV radiation up to 1.38 gm/cm3. Dielectric constant value k = 2.7 was achieved for UV treated samples. Investigation suggests that low-k films having lower k value may have potential applications as ILD for ULSI technology.