Resolving Abnormal Target Erosion in High Frequency Magnetron Discharge

解决高频磁控管放电中靶材异常侵蚀问题

• 批准号: 1724941
• 负责人: Qi Fan
• 金额: $ 30万
• 依托单位: Michigan State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2022-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1724941&HistoricalAwards=false
• 关键词: Resolving; Abnormal; Target; Erosion; Frequency

Radio frequency (RF) magnetron sputtering is an essential technology for manufacturing a broad variety of high-quality thin films. The ceramic targets, the source of the thin film coating material, consumed during the RF sputtering process are expensive, thus efficient target consumption is highly desirable in lowering manufacturing costs. Incomplete understanding of the ceramic target etching mechanisms occurring during RF magnetron sputtering results in poor target use rates (~30%). This award supports fundamental research aimed at understanding RF magnetron discharges and how they induce target consumption. New knowledge obtained on the complicated RF discharge processes will contribute to plasma science and technology, and will ultimately provide guidance on efficient RF magnetron design. Results from the research are expected to double the use rates of target materials. This will have a positive impact on many industrial fields including large-area optical coatings, energy storage, displays, solar energy, and semiconductor devices. The annual market of these fields has reached over $500 billion and is growing continuously. This project will strengthen university-industry collaborations and economic competitiveness of the U.S. by greatly reducing manufacturing costs of thin films. It will also contribute to workforce development by attracting and training graduate and undergraduate students in science and engineering.RF magnetron sputtering is essentially determined by the non-uniform electromagnetic fields that vary with time and in space. Charged particles that lead to the sputtering of the target undergo complicated interactions with the non-uniform fields. Understanding high-frequency plasma discharges under the confinement of magnetic fields is a challenge and holds strong scientific appeal. Despite the scientific community's strong interest in high-frequency plasma discharges, knowledge in RF magnetron sputtering is very limited, which results in unsatisfactory RF magnetrons. In fact, current magnetrons are designed for achieving optimum performance in direct current (DC) sputtering, which is used for target materials that are electrically conducting like metals. When this same magnetron is used for RF sputtering of insulator targets, it is extremely ineffective and produces an abnormal erosion profile completely different from that in DC sputtering. Specifically, the intensively etched region under DC sputtering is the least eroded under RF sputtering. To understand the mechanisms of the abnormal RF target erosion and fill the knowledge gap, the research team hypothesizes a 'localized charge effect', which assumes that electrons in RF magnetron discharges preferentially accumulate and stay immobile on the insulator target surface near the magnet poles to attract ions to sputter these regions. This hypothesis is unexpected from the existing knowledge on magnetron sputtering and is thus potentially transformative. The research includes two major tasks: 1) modeling of RF magnetron discharges, and 2) verifying the 'localized charge effect' by designing a highly efficient RF magnetron through modeling and experimentally testing.

射频（RF）磁控溅射是制造各种高质量薄膜的基本技术。在RF溅射工艺期间消耗的陶瓷靶（薄膜涂层材料的来源）是昂贵的，因此在降低制造成本方面非常期望有效的靶消耗。对RF磁控溅射过程中发生的陶瓷靶蚀刻机制的不完全理解导致靶使用率低（约30%）。该奖项支持旨在了解RF磁控管放电及其如何引起目标消耗的基础研究。 在复杂的射频放电过程中获得的新知识将有助于等离子体科学和技术，并最终将提供有效的射频磁控管设计的指导。研究结果预计将使目标材料的使用率翻一番。这将对许多工业领域产生积极影响，包括大面积光学涂层，储能，显示器，太阳能和半导体器件。这些领域的年市场已超过5000亿美元，并在不断增长。该项目将通过大大降低薄膜的制造成本来加强大学与产业的合作和美国的经济竞争力。它还将通过吸引和培训科学和工程专业的研究生和本科生来促进劳动力发展。射频磁控溅射基本上是由随时间和空间变化的非均匀电磁场决定的。导致靶溅射的带电粒子与非均匀场发生复杂的相互作用。了解磁场约束下的高频等离子体放电是一项挑战，具有强大的科学吸引力。尽管科学界对高频等离子体放电有着浓厚的兴趣，但对RF磁控管溅射的了解非常有限，这导致RF磁控管不令人满意。事实上，目前的磁控管被设计用于在直流（DC）溅射中实现最佳性能，其用于像金属一样导电的靶材料。当该相同的磁控管用于绝缘体靶的RF溅射时，它是极其无效的，并且产生与DC溅射中完全不同的异常侵蚀轮廓。具体地，在DC溅射下的强烈蚀刻区域在RF溅射下是最少侵蚀的。为了理解异常RF靶侵蚀的机制并填补知识空白，研究小组假设了“局部电荷效应”，该效应假设RF磁控管放电中的电子优先在磁极附近的绝缘体靶表面上积累并保持不动，以吸引离子溅射这些区域。这个假设是从磁控溅射的现有知识出乎意料的，因此是潜在的变革。本研究包含两个主要的工作：1）建立射频磁控管放电的模型; 2）通过建立模型和实验测试，设计一个高效率的射频磁控管，验证“局部电荷效应”。

项目成果

Methylene Blue Adsorption by Plasma Re-Activated Carbon

等离子体再活性炭吸附亚甲蓝

• DOI: 10.4236/jwarp.2021.1310041
• 发表时间: 2021
• 期刊: Journal of Water Resource and Protection
• 作者: Mackinder, Madeline A.;Wang, Keliang;Fan, Qi Hua
• 通讯作者: Fan, Qi Hua

Comparison of 1D and 2D particle-in-cell simulations for DC magnetron sputtering discharges

• DOI: 10.1063/5.0029353
• 发表时间: 2021-01-01
• 期刊: PHYSICS OF PLASMAS
• 影响因子: 2.2
• 作者: Zheng, Bocong;Fu, Yangyang;Fan, Qi Hua
• 通讯作者: Fan, Qi Hua

Electron dynamics in radio frequency magnetron sputtering argon discharges with a dielectric target

• DOI: 10.1088/1361-6595/abe9f9
• 发表时间: 2021-02
• 期刊: Plasma Sources Science and Technology
• 影响因子: 3.8
• 作者: B. Zheng;Yangyang Fu;Keliang Wang;T. Schuelke;Q. Fan

Enhancement of Ohmic heating by Hall current in magnetized capacitively coupled discharges

• DOI: 10.1088/1361-6595/ab419d
• 发表时间: 2019-09
• 期刊: Plasma Sources Science and Technology
• 影响因子: 3.8
• 作者: B. Zheng;Keliang Wang;T. Grotjohn;T. Schuelke;Q. Fan

Transition characteristics and electron kinetics in microhollow cathode discharges

• DOI: 10.1063/5.0033282
• 发表时间: 2021-01
• 期刊: Journal of Applied Physics
• 影响因子: 3.2
• 作者: Yangyang Fu;B. Zheng;Peng Zhang;Q. Fan;J. Verboncoeur