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Corresponding Author

Da-Quan Yu(yudaquan@xmu.edu.cn);
Ming Li(mingli90@sjtu.edu.cn)

Abstract

With the slow development of Moore's Law, the high density and miniaturization of microelectronic devices put forward higher requirements for advanced packaging technology. As a key technology in 2.5D/3D packaging, interposer technology has been extensively studied. According to different interposer materials, it is mainly divided into organic interposer, silicon interposer and glass interposer. Compared with the through silicon via (TSV) interconnection, the through glass via (TGV) interposer has received extensive attention in the 2.5D/3D advanced packaging field for its advantages of excellent high-frequency electrical characteristics, simple process, low cost, and adjustable coefficient of thermal expansion (CTE). However, the thermal conductivity of glass (about 1 W·m-1·K-1) is much lower than that of silicon (about 150 W·m-1·K-1), thus, the glass interposer has serious heat dissipation problems. In order to obtain a high-quality TGV interposer, not only an efficient and low-cost via preparation process, but also a defect-free filling process is required. The challenges faced by glass interposer is mainly concentrated in these two aspects. This review firstly introduces the preparation process of TGV, such as ultra-sonic drilling (USD), ultra-sonic high speed drilling (USHD), wet etching, deep reactive ion etching (DRIE), photosensitive glass, laser etching, laser induced deep etching (LIDE), etc. Then it summarizes the defect-free filling of TGV, and outlines several filling mechanisms and some current filling processes of TGV, such as bottom-up filling mechanisms, butterfly filling mechanisms and conformal filling mechanisms. Among the filling mechanisms of the above three filling methods, the filling method of bottom-up is the most studied one, and many scholars have given relevant explanations. Currently, the main ones that are commonly used are the diffusion-consumption mechanism, curvature enhanced adsorbate coverage mechanism (CEAC), convection dependent adsorption mechanism (CDA), and S-shaped negative differential resistance theory. In the process of TGV filling, the type and concentration of base bath, additives and electroplating process will affect the filling status of TGV. At present, the constant current plating mode is most commonly used in the process of TGV filling. Then the research progress of TGV electroplating additives is introduced, including the action mechanism of typical additives and the current research status of some new additives. Through glass via technology can be filled with the synergistic action of accelerators, suppressors and levelers. Finally, the practical application of TGV is briefly reviewed, for example, glass interposer is used in 3D integrated passive device (IPD), embedded glass fan-out technology (eGFO), integrated antenna packaging, micro-electro-mechanical system (MEMS), multi-chip module packaging, as well as the applications in the field of optical integration technology.

Graphical Abstract

Keywords

interposer, through glass via, filling mechanisms, filling process, additives

Publication Date

2022-06-28

Online Available Date

2022-06-28

Revised Date

2022-01-21

Received Date

2021-11-08

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