Wide temperature range through silicon vias made of Invar and spin-on glass for interposers and MEMS

Abstract

Through silicon vias (TSVs) are used e.g. to create electrical connections through MEMS wafers or through silicon interposers used in 2.5D packaging. Currently available technologies do not address situations in which TSVs through unthinned wafers have to withstand large temperature variations. We propose using ferromagnetic Invar metal alloy for this purpose due to its low mismatch in heat induced strain in comparison to silicon. We demonstrate the suitability of a magnetic assembly process for Invar TSV fabrication and the use of spin-on glass as a TSV insulator. We demonstrate TSVs, with contact pads, that tolerate temperature cycling between -50 °C and 190 °C and can withstand elevated temperatures of at least up to 365 °C.

Vacuum assisted liquified metal (VALM) TSV filling method with superconductive material

“…All the measured configurations show an ohmic behavior of the In-filled vias over the investigated voltage range. The obtained resistivity for a single via is as low as 593.6 μ m, which is in line with prior works [5,6].…”

“…TSV filling by electroplating and electroless plating is typically time-consuming and is hardly void-free, especially for high aspect ratio (HAR) vias [4]. Silver inkjet printing [5] and magnetic assembly of Ni rods [6,7] have been recently reported to improve vias filling. However, these filling methods show limitations in substrate choice, via depth, processing time or temperature budget.…”

Through Silicon Vias With Invar Metal Conductor for High-Temperature Applications

“…We provide a detailed description of the fabrication and characterization of Invar TSVs [24]. The fabricated Invar TSVs are temperature cycled between -50…”