光诱导自组装制备笼状硅基杂化介微孔超低介电材料的研究

Ultra-low dielectric constant (κ) materials are highly desirable for the development of microelectronic industry. At present, porous materials is one of the most promissing ultra-low k materials, which has the shortages of poor hydrophobic and mechanical properties, complicated synthesis process, using expensive porogen agent, et al. In order to solve those aformentioned problems, this proposal supposes to synthesize fluoronated alkyl group functionalized Polyhedral Oligomeric Silsesquioxane (F-POSS) micro-meso hierachical porous hybrid materials as a new generation of high performance ultra-low κ materials, by combining the excellent thermal, chemical and mechanical properties of POSS, as well as its constitutive nano-porous cage structure. The project intends to access F-POSS hierachical porous hybrid thin films by using newly designed and synthesized series of mono long alkyl-chain based ester group functionalized POSS cage as precursor and template via a light-induced self-assembly process, which is a simple, efficient, porogenic agent and organic solvent free, green methodology. The main thermodynamic and kinetic aspects of photochemical reaction conditions impacting the self-assembly process of the thin film on the substrate surface will be well explored by using different materials characterization techniques. Meanwhile, the formation mechanism, regulatory method of film’s micro-structure, the relationship between micro-structure and dielectric performance will also be investigated. Thus, the successful conduction of this project will provide theoretical support for the application of F-POSS porous hybrid thin films as ultra-low κ materials; and will be very helpful for the development of other new hybrid materials.

超低介电常数（κ）材料是微电子产业发展迫切需要攻克的关键新材料。针对目前最具应用潜力的多孔超低κ材料疏水、机械性能较差，制备过程繁琐，使用昂贵的致孔剂等问题，本申请提出氟代烷基酯功能化的多面体低聚倍半硅氧烷（F-POSS）介微孔杂化材料作为新一代高性能超低κ薄膜材料的新思路。项目拟利用POSS基团优异的热、化学、机械稳定性和其本构纳米微孔结构，设计合成系列新型长链烷基酯单修饰的笼状POSS硅氧烷作为前驱体兼模板剂，通过简单、高效、无致孔剂和无有机溶剂条件下的光诱导自组装方法制备疏水F-POSS介微孔杂化薄膜；运用现代材料表征技术，探索光化学反应条件等热力学和动力学因素对材料在基底表面的自组装过程影响，深入理解薄膜微结构的形成机理、调控方法，及其与介电等性能之间的构效关系。项目的成功实施将为F-POSS应用于超低κ材料的可能性提供理论支撑，并为发展其它杂化材料的设计合成研究提供新思路。

本项目基于有序聚硅氧烷材料，提供了一种超低介电薄膜的光诱导自组装聚合的新型合成方法，其工艺过程简单、可控、高效、环保。通过详细考察前驱体结构，光化学反应条件等热力学和动力学因素对材料的自组装微结构和介电、疏水等性能的影响，揭示聚硅氧烷薄膜微结构与性能之间的构效关系，并在此基础上探讨了其光诱导自组装机理。首先以烷基桥连的双功能化硅烷为前驱体，商品化的PAG103为引发剂，在405 nm可见光照下自组装聚合形成了有序层状聚硅烷薄膜，测试表明其具有良好的疏水（水接触角可达129.5°）、弹性模量（E=4.4 GPa）和较低的介电常数（k=2.75），优异的介电损耗性能（0.005）,证明了环境友好的LED可见光诱导自组装制备技术的可行性。非常低的光照强度和可见光照射可以有效实现聚合，这对于涂层制备和光聚合的室外大规模应用具有重要的意义。其次通过不对称双-甲硅烷基化烷基三甲氧基硅烷前体的自组装溶胶-凝胶光聚合，利用甲氧硅基之间-CH2-CH2-基团的空间位阻效应，在有序聚硅氧烷薄膜中引入额外的纳米孔洞，使得该薄膜具有优异低的低介电性能（k=2.14）。通过与其同分异构体的对比研究表明，化学组成形同情况下，揭示了孔隙率是决定薄膜介电性能的决定性因素。最后利用设计合成的十六烷基酯单功能化的T8笼形硅氧烷前驱体，通过简单、高效、绿色的光诱导自组装法和氟代醇酯交换后处理，开发了介微孔氟代聚硅氧烷超低介电薄膜。引入T8POSS笼和介孔孔道，使得该薄膜具有超低的介电常数值（k=1.8），同时由于POSS笼的晶体结构，使得薄膜具有较好的机械强度（3.6 GPa）。由于氟代乙基的疏水效应，使得薄膜具有一定的疏水性，解决了潮湿环境中介电稳定性的难题。本项目的部分成果已发表SCI论文4篇，申请国际发明专利1项，中国发明专利3项（已授权1项），实用新型专利2项（已授权2项），并培养硕士研究生3名。项目投入直接经费20万元，支出14.1563万元，各项支出基本与预算相符。剩余经费5.8437万元，将继续用于本项目研究后续支出。