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）是微电机电系统（MEMS）的有前途的材料，特别是对于在MHz-GHz频率范围内运行的设备。 MEMS微结构中的一个关键步骤是将压电层蚀刻到基础电极材料的等离子体蚀刻。对ARDEDYNE DALSA半导体在AR-BCL3-CL2等离子体化学上进行的Aln薄膜的蚀刻特性的初步研究表明，根据等离子条件的粗糙度，沟槽底部具有粗糙的锥体特征。此外，在模式的侧壁上观察到蚀刻副产品的重要重新沉积，这对于大多数应用来说是不可接受的。柱状ALN血浆蚀刻的其他并发症不仅归因于该材料的多组分性质，从而导致更复杂的表面化学性质，而且还归因于其柱状微结构产生的血浆蚀刻反应不仅在最高表面上，而且在整个晶界中都更深。通过UDEM和Teledyne-Dalsa之间的这种新的合作，我们想了解与表面粗糙动力学相关的特定方面和MEMS柱状ALN等离子体蚀刻中的特征曲线演变。拟议的研究基于我们小组在低温等离子体物理学及其在复杂材料处理中的应用。它还可以利用UDEM的独特基础架构，以等离子体蚀刻反应器，等离子体诊断和特征配置模拟器以及Teledyne-Dalsa的微加工和材料表征工具。由于这项研究将与Teledyne-Dalsa密切合作进行，因此预计本研究产生的知识将在其优化和开发等离子体蚀刻过程和食谱的优化和开发中起着至关重要的作用，这些过程和食谱在战略上需要应对基于ALN的设备制造中的当前和未来挑战。对于加拿大的其他公司来说，它也应肯定，以处理具有复杂纳米结构的材料的蚀刻。