A method for alleviating the effect of pinhole defects in inter-metal dielectric films
Xiaoxiao Song1,Qiu Wang1, Huafeng Liu1，Guangbin Dou2, Hao Li3, Wenjie Wu1, Fangjing Hu1, Ji Fan1, Jinquan Liu1 and Liang-Cheng Tu1,4
1 MOE Key Laboratory of Fundamental Physical Quantities Measurement & Hubei Key Laboratory of Gravitation and Quantum Physics, PGMF and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China
2 Department of Electrical and Electronic Engineering, Optical and Semiconductor Devices Group, Imperial College London, London SW7 2AZ, United Kingdom
3 Beijing Institute of Spacecraft Environment Engineering, Beijing, People's Republic of China
4 TianQin Research Center for Gravitational Physics and School of Physics and Astronomy, Sun Yat-sen University (Zhuhai Campus), Zhuhai, People's Republic of China
Published 12 December 2018 • © 2018 IOP Publishing Ltd
Journal of Micromechanics and Microengineering, Volume 29, Number 1
Abstract
As the insulation layers between two metal layers, inter-metal dielectric (IMD) films are widely used in integrated circuits (IC) and micro-electromechanical-systems (MEMS) devices. Commonly used IMD materials, such as silicon dioxide and silicon nitride, can be deposited on the metal surface using either physical vapor deposition (PVD) or chemical vapor deposition (CVD). However, due to the imperfections of deposition processes and surface cleanliness, defect-free of an IMD film cannot be guaranteed. As a common defect of an IMD film, pinhole is a tiny via of IMD film that can result in failures of short-circuit or current leakage between two metal layers and therefore decrease the fabrication yield. Reported methods for healing the pinhole defect require light-transmitting substrate, suspended structures, high-temperature annealing processes and none of them is universal. Therefore, we propose a metal etching method that uses metal etchants to etch the underlying metals through the pinholes of the IMD film. The etched area is reasonably larger than the pinhole; therefore, although the following upper metal deposition fills the pinhole, there is no electrical connection between the lower and upper metal features through the pinhole. Results of a series of experiments prove that the proposed method is feasible, valid, operable and reliable. Therefore, the proposed method is promising to be used for many IMD-based applications for either discovering pinholes or healing pinhole induced defects.
DOI： https://doi.org/10.1088/1361-6439/aaf376
http://iopscience.iop.org/article/10.1088/1361-6439/aaf376#references
