Electrical and mechanically robust, porous, ultra-low dielectric constant materials

电气和机械坚固、多孔、超低介电常数材料

• 批准号: 355552-2008
• 负责人: Tsui, Ting
• 金额: $ 1.46万
• 依托单位: University of Waterloo
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2011
• 资助国家: 加拿大
• 起止时间: 2011-01-01 至 2012-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=482747
• 关键词: Electrical; mechanically; robust; porous; ultra

With the increasing demand of integrated circuits (IC) computational speed performance, new nano-fabrication techniques and novel materials are needed. One of the most noticeable recent developments in the IC industry is the deployment of copper interconnects and ultra-low dielectric constant (ULK) materials in back-end-of-line structures. Interconnect lines are nanometer-scale metal wires used to connect transistors together. To avoid electrical shorts between these nano-wires and to provide mechanical support for the IC devices, ULK materials are used to insulate these metal wires. The migration of copper/ULK from the out-dated aluminum/silicon dioxide technology is to reduce signal delay by the resistances of interconnect line and the capacitance cross-talks between them. In the future, IC technology with the characteristic transistor gate length smaller than 22 nm (22 nm technology node) will consist of ULK materials with target dielectric constants less than 2.1 To achieve this objective, the ULK will be incorporated with nanometer-scale empty voids or pores. This new class of material is commonly referred to as porous-ULK and can be produced by using the porogen-subtraction method. Organic template agents (porogen) are introduced into the silicate matrix material by using the plasma-enhanced chemical vapor deposition (PECVD) techniques. They will be subsequently removed by a vaporization process using UV radiation at high temperature in an ultra-high-vacuum chamber. Depending on the amount of porogen used during the PECVD process, the final porosity in the porous-ULK film can be in the range of 20% to 40%. However, this technique has drawbacks which limit its application. This includes the difficulty of producing pores with diameters smaller than 2 nm which is the 22 nm technology node requirement. The UV cure process may increase the dielectric constant of the porous-ULK by modifying its molecular structures. Finally, as expected, the introduction of porosity into the silicate film reduces its mechanical and fracture strength. It is the goal of this research to understand the causes of these degradations and provide solutions by inventing new fabrication techniques.

随着对集成电路（IC）计算速度性能的需求不断增加，需要新的纳米制造技术和新型材料。 IC 行业最近最引人注目的发展之一是在后端结构中部署铜互连和超低介电常数 (ULK) 材料。互连线是用于将晶体管连接在一起的纳米级金属线。 为了避免这些纳米线之间发生电短路并为 IC 器件提供机械支撑，使用 ULK 材料来绝缘这些金属线。从过时的铝/二氧化硅技术迁移到铜/ULK是为了通过互连线的电阻和互连线之间的电容串扰来减少信号延迟。未来，特征晶体管栅极长度小于22纳米（22纳米技术节点）的IC技术将由目标介电常数小于2.1的ULK材料组成。为了实现这一目标，ULK将融入纳米级的空洞或孔隙。这种新型材料通常被称为多孔 ULK，可以通过使用致孔剂扣除方法来生产。通过使用等离子体增强化学气相沉积 (PECVD) 技术将有机模板剂（致孔剂）引入硅酸盐基质材料中。随后将在超高真空室中使用高温紫外线辐射通过汽化过程去除它们。根据 PECVD 过程中使用的致孔剂的量，多孔 ULK 薄膜的最终孔隙率可以在 20% 至 40% 的范围内。然而，该技术存在缺陷，限制了其应用。这包括难以产生直径小于2纳米的孔隙，这是22纳米技术节点的要求。 UV固化过程可以通过改变多孔-ULK的分子结构来增加其介电常数。最后，正如预期的那样，硅酸盐薄膜中引入孔隙会降低其机械强度和断裂强度。这项研究的目标是了解这些退化的原因并通过发明新的制造技术提供解决方案。