Study of precision control of metal-assisted wet-chemical etching of Si using metal multi-layer as a catalyst

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K04916
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 28050:Nano/micro-systems-related
• Research Institution: Kansai University
• Principal Investigator: Tomohiro Shimizu 関西大学, システム理工学部, 教授 (80581165)
• Co-Investigator(Kenkyū-buntansha): 新宮原 正三 関西大学, システム理工学部, 教授 (10231367) ; 伊藤 健 関西大学, システム理工学部, 教授 (50426350)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: MacEtch / Mace / Si加工 / MEMS / TSV

Outline of Final Research Achievements

To improve the Meta-assisted chemical Etching (MacEtch) process to be applicable to the manufacturing of Si devices, hard-diffusion materials used as catalysts or the introduction of diffusion barrier layers between the noble metal and Si are required to eliminate undesirable metal diffusion into the Si substrate, as well as formation of well-defined vertical holes in the substrate by this method. In this study, the usefulness of a metal interlayer interposed between the metal catalyst and Si was demonstrated for the formation of vertical microscale holes in a Si(100) substrate by MacEtch, and the effect of the interlayer was indicated. Additionally, we also showed additives of etching solution is also important to obtain well-defined vertical Si holes using MacEtch.

Free Research Field

ナノマイクロ加工

Academic Significance and Societal Importance of the Research Achievements

AuをSiに直接製膜する場合は、慣例的にTiが密着層が用いられてきた。Au触媒を用いたSi基板の湿式エッチングにおいても、密着層としてTiが用いてきたが、本研究により密着層としての役割だけでなく、Au-Siの相互拡散を抑止し、ランダムエッチングを防ぐ効果があることが初めて明らかとなった。ランダムエッチングの抑止は湿式Si加工の信頼性を向上し、精密さ信頼性が必要とされる用途にも今後応用が期待できる。