Preparation of Ultra Low- k Porous SiOCH Films from Ring-Type Siloxane with Unsaturated Hydrocarbon Side Chains by Spin-On Deposition

• Published in: Chinese physics letters 2010-02, Vol.27 (2), p.270-272
• Main Author: 杨春晓 张驰 孙清清 徐赛生 张立峰 施煜 丁士进 张卫
• Format: Article
• Language: English
• Subjects: 不饱和烃; 硅氧烷; 薄膜制备; 超低介电常数
• ISSN: 0256-307X; 1741-3540
• DOI: 10.1088/0256-307X/27/2/027701

An ultra-low-dielectric-constant （ultra low-k, or ULK） porous SiOCH film is prepared using a single ring-type siloxane precursor of the 2,4,6,8-tetravinyl-2,4,6,8-tetramethylcyclotetrasiloxane by means of spin-on deposition, followed by crosslinking reactions between the precursor monomers under UV irradiation. The as-prepared film has an ultra low k of 2.41 at 1 MHz due to incorporation of pores and hydrocarbon crosslinkages, a leakage current density of 9.86×10-7 A/cm2 at 1 MV/cm, as well as a breakdown field strength of ~1.5 MV/cm. Further, annealing at 300°C results in lower k （i.e., 1.94 at 1 MHz）, smaller leakage current density （2.96×10-7 A/cm2 at 1 MV/cm） and higher breakdown field strength （about 3.5 MV/cm）, which are likely caused by the short-ranged structural rearrangement and reduction of defects in the film. Finally, the mechanical properties and surface morphology of films are also evaluated after different temperature annealing.