An optimized through-via bottom-up method for simultaneous-filling TSVS of different aspect-ratios and its potential application on high-frequency passive interposer. (July 2020)

• Record Type: Journal Article
• Authors: Zhang, Weibo; Gu, Jiebin; Xu, Gaowei; Luo, Le; Li, Xinxin
• Is Part Of: Microelectronics journal. Volume 101(2020)
• Publication Date: 2020-07
• Subjects: Interposer -- Coaxial TSV -- Radio-frequency system-in-package -- Through-via electroplating -- 2.5D/3D integration -- Simultaneously filling; Microelectronics -- Periodicals; Microélectronique -- Périodiques; Microelectronics; Electronic journals; Journals - contents and abstracts; Periodicals; 621.3805
• DOI: 10.1016/j.mejo.2020.104798
• Languages: English
• ISSNs: 0959-8324

Abstract

Abstract: Passive interposer has become an attractive integrator for 2.5D/3D integration. TSV is the key technology for passive interposer. Coaxial-like transmission structure provides a low-cost solution of shielding TSV for high frequency application. Impedance matching needs coaxial-like TSVs to usually have different diameters. This paper presents an optimized through-via bottom-up filling method, which enables simultaneously copper filling TSVs with different aspect ratios. The demonstrated coaxial-like TSV structure have one signal-TSV and six grounded-TSVs. A potential voids problem of the filling method is identified and solved by adding suppressor. Simultaneously filling of signal-TSV and grounded-TSVs was realized by adjusting electroplating parameters, e.g. current density and stirring rate. The measured result of fabricated coaxial-like TSVs is comparable to the simulation. The result verifies that with this optimized filling method, the design of passive interposer equipped with coaxial-like vias can be more flexible and the impedance matching between TSVs and other components can be easily realized for high frequency applications.