Study on Low Dielectric Material

• Main Authors: Chang, Shiu-Ju, 張秀如
• Other Authors: Chen-Yen Chang
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/38357300387503988385

碩士 === 國立交通大學 === 電子工程學系 === 85 === Interconnect delay is a performance-liming factor for ULSI circuits when feature size is scaled into the deep submicron region. Using low dielectric constant material for the interlayer insulator is an effective way to solve the problem. We study three kinds of low dielectric constant material, including fluorine doped oxide( SiOF), methylsilsesquioxane spin on polymer and hydrogen silsesquioxane spin on glass. PECVD fluorine doped oxide( SiOF) is a popular way to reduce the dielectric constant, but it is reported that SiOF film with high level of fluorine incorporation have been shown to be unstable because of moisture absorption. In this work, NH3 plasma post-treatment are applied to as-deposited SiOF films. Moisture resistance and dielectric constant stability are investigated. We found that NH3 plasma post-treatment is quite efficient to enhance the capability of moisture absorption resistance of SiOF. In addition, two novel SOG material with permittivity lower than silicon dioxide interlevel dielectric have been developed. Those SOG can offer a k of less than 3.0. Two kinds of low k SOG are investigated, one is organic material-methylsilsesquioxane, the other is inorganic-hydrogen silsesquioxane. These spin on glass can offer low dielectric constant (~2.7) on the optimal conditions. The intrinsic properties and thermal stability of these spin on glass are investigated. We found that the thermal stability of methylsilsesquioxane is good because of Si-C bone in the film, and the thermal processing of hydrogen silsesquioxaone must be done carefully to attain the lowest dielectric constant.