Study of the surface roughening dynamics and feature profile evolution in plasma etching of AIN thin films for advanced MEMS microfabrication

研究用于先进 MEMS 微加工的 AIN 薄膜等离子蚀刻中的表面粗糙化动力学和特征轮廓演变

• 批准号: 418183-2011
• 负责人: Stafford, Luc
• 金额: $ 1.82万
• 依托单位: Université de Montréal
• 依托单位国家: 加拿大
• 项目类别: Engage Grants Program
• 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=494986
• 关键词: Study; surface; roughening; dynamics; feature

Aluminium nitride (AlN) is a promising material for MicroElectroMechanical Systems (MEMS), particularly for devices operating in the MHz-GHz frequency range. One critical step in MEMS microfabrication is the plasma etching of the piezoelectric layer down to the underlying electrode material. Preliminary investigations of the etching characteristics of AlN thin films with a columnar microstructure performed at Teledyne DALSA Semiconductor in Ar-BCl3-Cl2 plasma chemistries have shown rough, pyramidal features at the bottom of the trenches with roughness as large as 0.5 µm depending on the plasma conditions. In addition, important redeposition of etching by-products was observed on the sidewalls of the patterns, which is unacceptable for most applications. Additional complications in plasma etching of columnar AlN are due not only to the multi-component nature of this material, resulting in a more sophisticated surface chemistry, but also to its columnar microstructure yielding plasma etching reactions not only on the topmost surface but also deeper in the bulk through grain boundaries. Through this new collaboration between UdeM and Teledyne-DALSA, we would like to gain insights into specific aspects related to the surface roughening dynamics and feature profile evolution in plasma etching of columnar AlN for MEMS. The proposed research builds on the expertise of our group in the physics of low-temperature plasmas and their applications to complex materials processing. It also capitalizes on the unique infrastracture of UdeM in terms of plasma etching reactors, plasma diagnostics, and feature profile simulators as well as the microfabrication and materials characterization tools of Teledyne-DALSA. Since this research will be performed in close collaboration with Teledyne-DALSA, it is expected that the knowledge generated from this study will play a crucial role in their optimization and development of plasma etching processes and recipes that are strategically needed to meet current and future challenges in AlN-based device manufacturing. It should also be benificial to other companies in Canada dealing with the etching of materials with a complex nanostructure.

氮化铝 (AlN) 是一种很有前途的微机电系统 (MEMS) 材料，特别是对于在 MHz-GHz 频率范围内工作的设备。 MEMS 微加工的一个关键步骤是对压电层进行等离子蚀刻直至下面的电极材料。 Teledyne DALSA Semiconductor 在 Ar-BCl3-Cl2 等离子体化学中对具有柱状微结构的 AlN 薄膜的蚀刻特性进行了初步研究，结果显示沟槽底部具有粗糙的金字塔形特征，其粗糙度高达 0.5 µm，具体取决于等离子体条件。此外，在图案的侧壁上观察到蚀刻副产物的重要再沉积，这对于大多数应用来说是不可接受的。柱状 AlN 等离子蚀刻的其他复杂性不仅是由于该材料的多组分性质，导致更复杂的表面化学，而且还因为其柱状微观结构不仅在最顶层表面上产生等离子蚀刻反应，而且还通过晶界在块体内产生更深的反应。通过 UdeM 和 Teledyne-DALSA 之间的新合作，我们希望深入了解与 MEMS 柱状 AlN 等离子蚀刻中的表面粗糙化动力学和特征轮廓演变相关的具体方面。拟议的研究建立在我们小组在低温等离子体物理学及其在复杂材料加工中的应用方面的专业知识的基础上。它还利用了 UdeM 在等离子体蚀刻反应器、等离子体诊断和特征轮廓模拟器以及 Teledyne-DALSA 的微加工和材料表征工具方面的独特基础设施。由于这项研究将与 Teledyne-DALSA 密切合作进行，因此预计从这项研究中获得的知识将在等离子蚀刻工艺和配方的优化和开发中发挥至关重要的作用，这些工​​艺和配方是应对基于 AlN 的器件制造中当前和未来挑战的战略需要。这也应该有利于加拿大其他从事复杂纳米结构材料蚀刻的公司。