Orientation control applicable Cu interconnect on the cutting edge of 3D devices and 3D-LSI

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K04223
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 21050:Electric and electronic materials-related
• Research Institution: Kitami Institute of Technology
• Principal Investigator: Takeyama Mayumi B. 北見工業大学, 工学部, 教授 (80236512)
• Co-Investigator(Kenkyū-buntansha): 佐藤 勝 北見工業大学, 工学部, 准教授 (10636682)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 集積回路 / Cu配線 / 配向制御 / 拡散バリヤ / 下地材料 / 信頼性 / 構造解析 / 熱的安定性

Outline of Final Research Achievements

We examine a thin TaWN film as a material candidate that satisfies characteristic of both an underlying material for the Cu(111) preferred orientation and thermally stable barrier against Cu diffusion. It became clear that the 5-nm thick TaWN film has excellent barrier properties of sufficiently suppressing the Cu diffusion even after annealing at 700 degree C for 1 h. Simultaneously, the Cu film on the 5-nm-thick TaWN film shows the (111) highly orientation. It was difficult to elucidate this mechanism, but it was clarified by introducing new measurement system. It was revealed that the structure of this barrier is based on the fcc-TaN with a slightly expand lattice and shows the (111) orientation, resulting in the lattice matching with Cu(111). It was found that the TaWN is useful as a material that has two different properties of the barrier material and underlying material for Cu(111) orientation. These results will be useful for future metallization technology.

Free Research Field

集積回路

Academic Significance and Societal Importance of the Research Achievements

これまでエピタキシャルの関係があるCu/Nbなどごく一部の材料のみがCu(111)配向をもたらす下地材料であり、比較的厚い膜が使われてきた。また、下地材料は拡散バリヤ性に乏しく、拡散バリヤとの2層構造をとることが、微細プロセスと相反することになり、Cu(111)配向の実現は困難を極めた。しかし、我々が実現した5nmの拡散バリヤ上でもCu(111)配向制御が可能であるという発見は、これまでにない新規性、独創性に富む有意義な結果である。同時に、将来配線上に形成されるデバイスの性能向上にとっても極めて有用な結果を示すことが期待され、新たな分野を確立できるほどの学術的意義がある。