Under-Bump Metallization Contact Resistance ( R ) Characterization at 10- \mu \text Polymer Passivation Opening

• Published in: IEEE transactions on components, packaging, and manufacturing technology (2011) Vol. 7; no. 10; pp. 1592 - 1597
• Main Authors: Lianto, Prayudi, King-Jien Chui, Bhushan, Bharat, Chua, H. M. Calvin, Leijun Tang, Chandra Rao, B. S. S., Xin Wang, Ai Long Wu, Yu Gu, Guan Huei See, Sundarrajan, Arvind
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01-10-2017; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Al oxide; Al pad; Contact resistance; contact resistance (<italic xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">Rc ); Electronic devices; Impact strength; Metallizing; Metals; organometallic; outgassing; Passivation; Passivity; polymer; Polymers; preclean; Purging; Residual gas; Resistance; Silicon compounds; Test vehicles; under-bump metallization (UBM)
• DOI: 10.1109/TCPMT.2017.2726118
• EISSN: 2156-3985
• ISSN: 2156-3950

Under-bump metallization R c is a critical metric for high-density interconnect in electronic devices. We developed a test vehicle to characterize the impact of unit processes on R c for 10-μm polymer passivation opening. We demonstrate that advanced preclean is necessary to achieve low (R c <; 20 mQ) for future node extendibility, owing to reduction of both Al oxide and organometallic formation. This is achievable through a combination of low-temperature (<;100°C) preclean and fast residual gas purging from the chamber. A mechanism is proposed to explain the role of preclean in R c performance. Influence of SiN etch on R c is also investigated, and it was found that Cl-chemistry is better than F-chemistry to achieve low R c .