Internal Stress and Atomic Transportation in Thin Film and Line Structure

薄膜和线结构中的内应力和原子传输

• 批准号: 10650092
• 负责人: HANABUSA Takao
• 金额: $ 2.24万
• 依托单位: The University of Tokushima
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10650092/
• 关键词: Thin film; Internal stress; Thermal stress; In-situ observation; Surface morphology; Stress migration; Preferred orientation; X-ray stress measurement; Cu膜; 熱サイクル; ストレスマグレーション

In order to investigate the property of atomic migration in high temperature region of aluminum and copper for the materials used in LSI technology, in-situ X-ray thermal stress measurement and optical as well as electronic observations of surface morphology of Al and Cu films.Al and Cu films deposited on a glass or a Si substrate by RF sputtering had strong < 111 > preferred orientation. Residual stress in an as-deposited state was tensile in all the case regardless of the RF power, Ar gas pressure and sputtering time. An in-situ thermal stress measurement was made by X-ray diffraction technique on the specimens under the heating and cooling cycles between RT and 200℃, 300℃, and 400℃. The tensile stress in the films almost diminished to zero level by increasing temperature to 100℃ and after that there was no significant change in the stress level up to the maximum temperature in each thermal cycle. In the cooling stage, the stress in the film changed to tensile but the increasing rate was small in the initial stage and became large in the final stage of low temperature range. It is due to the ability of grain boundary diffusion, surface diffusion and body diffusion. On the other hand, the variation of the thermal stress in films covered by thin AlN or TiN film was large during the thermal cycles because of the constraining of the atomic transportation by the protective film deposited on the surface of Al or Cu film.From SEM and AFM observations, it was cleared that hillocks and voids develop in the heating stage and cooling stage, respectively. Furthermore, the change in surface roughness and the appearance of recrystallization were observed in the heating stage by the in-situ laser microscopic investigation.

为了研究LSI技术用材料铝和铜在高温区的原子迁移特性，对Al和Cu薄膜进行了原位X射线热应力测量以及光学和电子学观察。通过射频溅射在玻璃或Si衬底上沉积的Al和Cu薄膜具有强的<111>择优取向。无论RF功率、Ar气压和溅射时间如何，沉积状态下的残余应力在所有情况下都是拉伸的。采用X射线衍射技术对样品在室温和200℃、300℃、400℃之间的加热和冷却循环下进行原位热应力测量。当温度升高到100℃时，薄膜中的拉伸应力几乎减小到零水平，之后在每个热循环中直至最高温度，应力水平没有显着变化。在冷却阶段，薄膜中的应力转变为拉伸应力，但初始阶段增加幅度较小，在低温范围的最终阶段增加幅度较大。这是由于晶界扩散、表面扩散和体扩散的能力。另一方面，由于Al或Cu膜表面沉积的保护膜对原子传输的限制，AlN或TiN薄膜覆盖的薄膜在热循环过程中热应力的变化很大。从SEM和AFM观察可以清楚地看出，在加热阶段和冷却阶段分别形成了小丘和空洞。此外，通过原位激光显微镜观察加热阶段表面粗糙度的变化和再结晶的出现。

项目成果

T. Hanabusa, K. Kusaka, et al: "Measurement and observation of voids and hillock formation of aluminum film"The Fifth International Conference on Residual Stresses, Ed. by T. Ericsson, M. Oden and A. Andersson. Vol. 2. 854-861 (1998)

T. Hanabusa、K. Kusaka 等人：“铝膜的空隙和小丘形成的测量和观察”第五届国际残余应力会议，Ed。

T.Hanabusa,K.Kusaka, et al.: "Measurement and observation of void and hillock formation of aluminum film"The Film International Conference on Residual Stresses Ed, by T.Ericsson, M.Oden. and A.Anderson. 2. 854-861 (1998)

T.Hanabusa、K.Kusaka 等人：“铝膜空隙和小丘形成的测量和观察”电影国际残余应力会议编辑，T.Ericsson、M.Oden。