Porous ultra-low-dielectric constant thin film fabrication system

多孔超低介电（p-ULK）材料的制备是近年来高性能集成电路（IC）材料研究的热点之一。这些新型材料用于绝缘铜互连线，以防止电短路，并减少后端线结构中的电阻-电容延迟。p-ULK薄膜的制造需要一套独特的硬件，这在大学实验室中是不常见的。它需要等离子体增强化学气相沉积（PECVD）腔室，该腔室具有递送硅酸盐基和有机模板液体前体的能力。p-ULK材料中的纳米尺寸空隙是通过将具有有机模板分子的沉积膜在真空和高温下暴露于高能（大于1kW）紫外辐射来产生的。该过程使有机分子蒸发并产生直径小于5nm的空空隙或孔。通过仔细控制沉积条件，使用该制造技术可实现40%体积的最佳孔隙率。这两种先进的处理系统，液体源PECVD和高能紫外线固化，都没有在滑铁卢大学校园。该提案中描述的新能力不仅将支持p-ULK领域的研究项目，还将支持其他新型材料的开发，例如非常薄（400 A或更小）的氮或氧掺杂碳化硅薄膜。这些薄膜可用于IC中的铜和氢扩散阻挡层。氮化硅薄膜的高能紫外光固化技术也在研究中，以促进应变硅晶体管技术的发展。

Fabrication of porous ultra-low-dielectric (p-ULK) materials has been one of the main focuses in high performance integrated circuit (IC) materials research in recent years. These novel materials are used to insulate copper interconnect lines to prevent electrical shorts and reduce the resistance-capacitance delay in the back-end-of-line structures. The fabrication of p-ULK thin films requires a unique set of hardware that is not commonly available in university laboratory. It requires a plasma-enhanced chemical vapor deposition (PECVD) chamber with the capability to delivery silicate based and organic template liquid precursors. Nanometer size voids in the p-ULK materials are produced by exposing as-deposited films with the organic template molecules to high energy (greater 1kW) ultraviolet radiation in vacuum and at high temperature. This process vaporizes the organic molecules and produces empty voids or pores smaller than 5 nm in diameter. With careful control of the deposition conditions, the optimal porosity of 40 % volume is achievable using this fabrication technique. Neither of these advanced processing systems, liquid sourced PECVD and high energy UV cure, is available on the University of Waterloo campus. The new capabilities described in this proposal will support research projects not only in the p-ULK area but also in development of other novel materials, such as very thin (400A or less) nitrogen or oxygen-doped silicon carbide thin films. These thin films can be used for copper and hydrogen diffusion barriers in the IC. The high energy UV curing techniques for silicon nitride thin films are also being investigated, for advancement of strained silicon transistor technology.